diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/api.yml b/spiffworkflow-backend/src/spiffworkflow_backend/api.yml
index 764ba543..84ada234 100755
--- a/spiffworkflow-backend/src/spiffworkflow_backend/api.yml
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/api.yml
@@ -699,6 +699,12 @@ paths:
         description: The unique id of an existing process instance.
         schema:
           type: integer
+      - name: process_identifier
+        in: query
+        required: false
+        description: The identifier of the process to use for the diagram. Useful for displaying the diagram for a call activity.
+        schema:
+          type: string
     get:
       tags:
         - Process Instances
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/process_instance_metadata.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/process_instance_metadata.py
index c9003594..f2e4c222 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/process_instance_metadata.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/process_instance_metadata.py
@@ -1,4 +1,4 @@
-"""Spiff_step_details."""
+"""Process_instance_metadata."""
 from dataclasses import dataclass
 
 from flask_bpmn.models.db import db
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py
index 1e85f722..50b73fba 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py
@@ -8,6 +8,10 @@ from marshmallow import INCLUDE
 from sqlalchemy import UniqueConstraint
 
 
+class SpecReferenceNotFoundError(Exception):
+    """SpecReferenceNotFoundError."""
+
+
 @dataclass()
 class SpecReference:
     """File Reference Information.
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/spiff_step_details.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/spiff_step_details.py
index 91d70116..9afb5d07 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/spiff_step_details.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/spiff_step_details.py
@@ -21,7 +21,7 @@ class SpiffStepDetailsModel(SpiffworkflowBaseDBModel):
         ForeignKey(ProcessInstanceModel.id), nullable=False  # type: ignore
     )
     spiff_step: int = db.Column(db.Integer, nullable=False)
-    task_json: str = deferred(db.Column(db.JSON, nullable=False))  # type: ignore
+    task_json: dict = deferred(db.Column(db.JSON, nullable=False))  # type: ignore
     timestamp: float = db.Column(db.DECIMAL(17, 6), nullable=False)
     completed_by_user_id: int = db.Column(db.Integer, nullable=True)
     lane_assignment_id: Optional[int] = db.Column(
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py
index 52bb1171..60deda84 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py
@@ -108,7 +108,7 @@ class Task:
         multi_instance_type: Union[MultiInstanceType, None] = None,
         multi_instance_count: str = "",
         multi_instance_index: str = "",
-        process_name: str = "",
+        process_identifier: str = "",
         properties: Union[dict, None] = None,
         process_instance_id: Union[int, None] = None,
         process_instance_status: Union[str, None] = None,
@@ -118,6 +118,7 @@ class Task:
         form_schema: Union[str, None] = None,
         form_ui_schema: Union[str, None] = None,
         parent: Optional[str] = None,
+        call_activity_process_identifier: Optional[str] = None,
     ):
         """__init__."""
         self.id = id
@@ -129,6 +130,7 @@ class Task:
         self.documentation = documentation
         self.lane = lane
         self.parent = parent
+        self.call_activity_process_identifier = call_activity_process_identifier
 
         self.data = data
         if self.data is None:
@@ -151,7 +153,7 @@ class Task:
         self.multi_instance_index = (
             multi_instance_index  # And the index of the currently repeating task.
         )
-        self.process_name = process_name
+        self.process_identifier = process_identifier
 
         self.properties = properties  # Arbitrary extension properties from BPMN editor.
         if self.properties is None:
@@ -177,7 +179,7 @@ class Task:
             "multi_instance_type": multi_instance_type,
             "multi_instance_count": self.multi_instance_count,
             "multi_instance_index": self.multi_instance_index,
-            "process_name": self.process_name,
+            "process_identifier": self.process_identifier,
             "properties": self.properties,
             "process_instance_id": self.process_instance_id,
             "process_instance_status": self.process_instance_status,
@@ -187,6 +189,7 @@ class Task:
             "form_schema": self.form_schema,
             "form_ui_schema": self.form_ui_schema,
             "parent": self.parent,
+            "call_activity_process_identifier": self.call_activity_process_identifier,
         }
 
     @classmethod
@@ -282,7 +285,7 @@ class TaskSchema(Schema):
             "multi_instance_type",
             "multi_instance_count",
             "multi_instance_index",
-            "process_name",
+            "process_identifier",
             "properties",
             "process_instance_id",
             "form_schema",
@@ -293,7 +296,7 @@ class TaskSchema(Schema):
     documentation = marshmallow.fields.String(required=False, allow_none=True)
     # form = marshmallow.fields.Nested(FormSchema, required=False, allow_none=True)
     title = marshmallow.fields.String(required=False, allow_none=True)
-    process_name = marshmallow.fields.String(required=False, allow_none=True)
+    process_identifier = marshmallow.fields.String(required=False, allow_none=True)
     lane = marshmallow.fields.String(required=False, allow_none=True)
 
     @marshmallow.post_load
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py b/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py
index c29cf214..026ed35d 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py
@@ -66,6 +66,7 @@ from spiffworkflow_backend.models.process_model import ProcessModelInfoSchema
 from spiffworkflow_backend.models.secret_model import SecretModel
 from spiffworkflow_backend.models.secret_model import SecretModelSchema
 from spiffworkflow_backend.models.spec_reference import SpecReferenceCache
+from spiffworkflow_backend.models.spec_reference import SpecReferenceNotFoundError
 from spiffworkflow_backend.models.spec_reference import SpecReferenceSchema
 from spiffworkflow_backend.models.spiff_logging import SpiffLoggingModel
 from spiffworkflow_backend.models.spiff_step_details import SpiffStepDetailsModel
@@ -1073,25 +1074,48 @@ def process_instance_report_column_list() -> flask.wrappers.Response:
 
 
 def process_instance_show(
-    modified_process_model_identifier: str, process_instance_id: int
+    modified_process_model_identifier: str,
+    process_instance_id: int,
+    process_identifier: Optional[str] = None,
 ) -> flask.wrappers.Response:
     """Create_process_instance."""
     process_model_identifier = modified_process_model_identifier.replace(":", "/")
     process_instance = find_process_instance_by_id_or_raise(process_instance_id)
     current_version_control_revision = GitService.get_current_revision()
-    process_model = get_process_model(process_model_identifier)
 
-    if process_model.primary_file_name:
+    process_model_with_diagram = None
+    name_of_file_with_diagram = None
+    if process_identifier:
+        spec_reference = SpecReferenceCache.query.filter_by(
+            identifier=process_identifier
+        ).first()
+        if spec_reference is None:
+            raise SpecReferenceNotFoundError(
+                f"Could not find given process identifier in the cache: {process_identifier}"
+            )
+
+        process_model_with_diagram = ProcessModelService.get_process_model(
+            spec_reference.process_model_id
+        )
+        name_of_file_with_diagram = spec_reference.file_name
+    else:
+        process_model_with_diagram = get_process_model(process_model_identifier)
+        if process_model_with_diagram.primary_file_name:
+            name_of_file_with_diagram = process_model_with_diagram.primary_file_name
+
+    if process_model_with_diagram and name_of_file_with_diagram:
         if (
             process_instance.bpmn_version_control_identifier
             == current_version_control_revision
         ):
             bpmn_xml_file_contents = SpecFileService.get_data(
-                process_model, process_model.primary_file_name
+                process_model_with_diagram, name_of_file_with_diagram
             ).decode("utf-8")
         else:
             bpmn_xml_file_contents = GitService.get_instance_file_contents_for_revision(
-                process_model, process_instance.bpmn_version_control_identifier
+                process_model_with_diagram,
+                process_instance.bpmn_version_control_identifier,
+                file_name=name_of_file_with_diagram,
             )
         process_instance.bpmn_xml_file_contents = bpmn_xml_file_contents
 
@@ -1409,7 +1433,8 @@ def process_instance_task_list(
         )
         if step_detail is not None and process_instance.bpmn_json is not None:
             bpmn_json = json.loads(process_instance.bpmn_json)
-            bpmn_json["tasks"] = step_detail.task_json
+            bpmn_json["tasks"] = step_detail.task_json["tasks"]
+            bpmn_json["subprocesses"] = step_detail.task_json["subprocesses"]
             process_instance.bpmn_json = json.dumps(bpmn_json)
 
     processor = ProcessInstanceProcessor(process_instance)
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py
index f972b672..152aab1c 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py
@@ -46,18 +46,24 @@ class GitService:
 
     @classmethod
     def get_instance_file_contents_for_revision(
-        cls, process_model: ProcessModelInfo, revision: str
+        cls,
+        process_model: ProcessModelInfo,
+        revision: str,
+        file_name: Optional[str] = None,
     ) -> str:
         """Get_instance_file_contents_for_revision."""
         bpmn_spec_absolute_dir = current_app.config["BPMN_SPEC_ABSOLUTE_DIR"]
         process_model_relative_path = FileSystemService.process_model_relative_path(
             process_model
         )
+        file_name_to_use = file_name
+        if file_name_to_use is None:
+            file_name_to_use = process_model.primary_file_name
         with FileSystemService.cd(bpmn_spec_absolute_dir):
             shell_command = [
                 "git",
                 "show",
-                f"{revision}:{process_model_relative_path}/{process_model.primary_file_name}",
+                f"{revision}:{process_model_relative_path}/{file_name_to_use}",
             ]
             return cls.run_shell_command_to_get_stdout(shell_command)
 
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py
index ffe69fd7..5edc526c 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_processor.py
@@ -551,7 +551,7 @@ class ProcessInstanceProcessor:
         """SaveSpiffStepDetails."""
         bpmn_json = self.serialize()
         wf_json = json.loads(bpmn_json)
-        task_json = wf_json["tasks"]
+        task_json = {"tasks": wf_json["tasks"], "subprocesses": wf_json["subprocesses"]}
 
         return {
             "process_instance_id": self.process_instance_model.id,
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py
index 46bd252b..5b2781a2 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py
@@ -302,6 +302,11 @@ class ProcessInstanceService:
         else:
             lane = None
 
+        if hasattr(spiff_task.task_spec, "spec"):
+            call_activity_process_identifier = spiff_task.task_spec.spec
+        else:
+            call_activity_process_identifier = None
+
         parent_id = None
         if spiff_task.parent:
             parent_id = spiff_task.parent.id
@@ -316,9 +321,10 @@ class ProcessInstanceService:
             multi_instance_type=mi_type,
             multi_instance_count=info["mi_count"],
             multi_instance_index=info["mi_index"],
-            process_name=spiff_task.task_spec._wf_spec.description,
+            process_identifier=spiff_task.task_spec._wf_spec.name,
             properties=props,
             parent=parent_id,
+            call_activity_process_identifier=call_activity_process_identifier,
         )
 
         return task
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/spec_file_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/spec_file_service.py
index c69f41c3..72f59d1f 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/spec_file_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/spec_file_service.py
@@ -171,13 +171,18 @@ class SpecFileService(FileSystemService):
                 ref.is_primary = True
 
             if ref.is_primary:
-                ProcessModelService.update_process_model(
-                    process_model_info,
-                    {
-                        "primary_process_id": ref.identifier,
-                        "primary_file_name": file_name,
-                    },
-                )
+                update_hash = {}
+                if not process_model_info.primary_file_name:
+                    update_hash["primary_process_id"] = ref.identifier
+                    update_hash["primary_file_name"] = file_name
+                elif file_name == process_model_info.primary_file_name:
+                    update_hash["primary_process_id"] = ref.identifier
+
+                if len(update_hash) > 0:
+                    ProcessModelService.update_process_model(
+                        process_model_info,
+                        update_hash,
+                    )
             SpecFileService.update_caches(ref)
         return file
 
diff --git a/spiffworkflow-backend/tests/spiffworkflow_backend/integration/test_process_api.py b/spiffworkflow-backend/tests/spiffworkflow_backend/integration/test_process_api.py
index 0070c5c9..4a0100d3 100644
--- a/spiffworkflow-backend/tests/spiffworkflow_backend/integration/test_process_api.py
+++ b/spiffworkflow-backend/tests/spiffworkflow_backend/integration/test_process_api.py
@@ -1167,6 +1167,60 @@ class TestProcessApi(BaseTest):
             xml_file_contents = f_open.read()
             assert show_response.json["bpmn_xml_file_contents"] == xml_file_contents
 
+    def test_process_instance_show_with_specified_process_identifier(
+        self,
+        app: Flask,
+        client: FlaskClient,
+        with_db_and_bpmn_file_cleanup: None,
+        with_super_admin_user: UserModel,
+    ) -> None:
+        """Test_process_instance_show_with_specified_process_identifier."""
+        process_model_id = "call_activity_nested"
+        process_model_identifier = self.create_group_and_model_with_bpmn(
+            client=client,
+            user=with_super_admin_user,
+            process_group_id="test_group_two",
+            process_model_id=process_model_id,
+            bpmn_file_location="call_activity_nested",
+        )
+        spec_reference = SpecReferenceCache.query.filter_by(
+            identifier="Level2b"
+        ).first()
+        assert spec_reference
+        modified_process_model_identifier = (
+            self.modify_process_identifier_for_path_param(process_model_identifier)
+        )
+        headers = self.logged_in_headers(with_super_admin_user)
+        create_response = self.create_process_instance_from_process_model_id(
+            client, process_model_identifier, headers
+        )
+        assert create_response.json is not None
+        assert create_response.status_code == 201
+        process_instance_id = create_response.json["id"]
+        client.post(
+            f"/v1.0/process-instances/{modified_process_model_identifier}/{process_instance_id}/run",
+            headers=self.logged_in_headers(with_super_admin_user),
+        )
+        show_response = client.get(
+            f"/v1.0/process-instances/{modified_process_model_identifier}/{process_instance_id}?process_identifier={spec_reference.identifier}",
+            headers=self.logged_in_headers(with_super_admin_user),
+        )
+        assert show_response.json is not None
+        assert show_response.status_code == 200
+        file_system_root = FileSystemService.root_path()
+        process_instance_file_path = (
+            f"{file_system_root}/{process_model_identifier}/{process_model_id}.bpmn"
+        )
+        with open(process_instance_file_path) as f_open:
+            xml_file_contents = f_open.read()
+            assert show_response.json["bpmn_xml_file_contents"] != xml_file_contents
+        spec_reference_file_path = os.path.join(
+            file_system_root, spec_reference.relative_path
+        )
+        with open(spec_reference_file_path) as f_open:
+            xml_file_contents = f_open.read()
+            assert show_response.json["bpmn_xml_file_contents"] == xml_file_contents
+
     def test_message_start_when_starting_process_instance(
         self,
         app: Flask,
diff --git a/spiffworkflow-frontend/src/components/ProcessInstanceListTable.tsx b/spiffworkflow-frontend/src/components/ProcessInstanceListTable.tsx
index 98b76df3..64b0a7e9 100644
--- a/spiffworkflow-frontend/src/components/ProcessInstanceListTable.tsx
+++ b/spiffworkflow-frontend/src/components/ProcessInstanceListTable.tsx
@@ -300,8 +300,13 @@ export default function ProcessInstanceListTable({
 
     checkFiltersAndRun();
     if (autoReload) {
-      refreshAtInterval(REFRESH_INTERVAL, REFRESH_TIMEOUT, checkFiltersAndRun);
+      return refreshAtInterval(
+        REFRESH_INTERVAL,
+        REFRESH_TIMEOUT,
+        checkFiltersAndRun
+      );
     }
+    return undefined;
   }, [
     autoReload,
     searchParams,
diff --git a/spiffworkflow-frontend/src/components/ReactDiagramEditor.tsx b/spiffworkflow-frontend/src/components/ReactDiagramEditor.tsx
index 11839e9c..a1be5efa 100644
--- a/spiffworkflow-frontend/src/components/ReactDiagramEditor.tsx
+++ b/spiffworkflow-frontend/src/components/ReactDiagramEditor.tsx
@@ -58,14 +58,14 @@ import HttpService from '../services/HttpService';
 import ButtonWithConfirmation from './ButtonWithConfirmation';
 import { makeid } from '../helpers';
 import { useUriListForPermissions } from '../hooks/UriListForPermissions';
-import { PermissionsToCheck } from '../interfaces';
+import { PermissionsToCheck, ProcessInstanceTask } from '../interfaces';
 import { usePermissionFetcher } from '../hooks/PermissionService';
 
 type OwnProps = {
   processModelId: string;
   diagramType: string;
-  readyOrWaitingBpmnTaskIds?: string[] | null;
-  completedTasksBpmnIds?: string[] | null;
+  readyOrWaitingProcessInstanceTasks?: ProcessInstanceTask[] | null;
+  completedProcessInstanceTasks?: ProcessInstanceTask[] | null;
   saveDiagram?: (..._args: any[]) => any;
   onDeleteFile?: (..._args: any[]) => any;
   onSetPrimaryFile?: (..._args: any[]) => any;
@@ -88,8 +88,8 @@ type OwnProps = {
 export default function ReactDiagramEditor({
   processModelId,
   diagramType,
-  readyOrWaitingBpmnTaskIds,
-  completedTasksBpmnIds,
+  readyOrWaitingProcessInstanceTasks,
+  completedProcessInstanceTasks,
   saveDiagram,
   onDeleteFile,
   onSetPrimaryFile,
@@ -227,7 +227,9 @@ export default function ReactDiagramEditor({
 
     function handleElementClick(event: any) {
       if (onElementClick) {
-        onElementClick(event.element);
+        const canvas = diagramModeler.get('canvas');
+        const rootElement = canvas.getRootElement();
+        onElementClick(event.element, rootElement);
       }
     }
 
@@ -350,12 +352,15 @@ export default function ReactDiagramEditor({
 
     function highlightBpmnIoElement(
       canvas: any,
-      taskBpmnId: string,
-      bpmnIoClassName: string
+      processInstanceTask: ProcessInstanceTask,
+      bpmnIoClassName: string,
+      bpmnRootElementId: string
     ) {
-      if (checkTaskCanBeHighlighted(taskBpmnId)) {
+      if (checkTaskCanBeHighlighted(processInstanceTask.name)) {
         try {
-          canvas.addMarker(taskBpmnId, bpmnIoClassName);
+          if (bpmnRootElementId === processInstanceTask.process_identifier) {
+            canvas.addMarker(processInstanceTask.name, bpmnIoClassName);
+          }
         } catch (bpmnIoError: any) {
           // the task list also contains task for processes called from call activities which will
           // not exist in this diagram so just ignore them for now.
@@ -394,21 +399,25 @@ export default function ReactDiagramEditor({
       // highlighting a field
       // Option 3 at:
       //  https://github.com/bpmn-io/bpmn-js-examples/tree/master/colors
-      if (readyOrWaitingBpmnTaskIds) {
-        readyOrWaitingBpmnTaskIds.forEach((readyOrWaitingBpmnTaskId) => {
+      if (readyOrWaitingProcessInstanceTasks) {
+        const rootElement = canvas.getRootElement();
+        readyOrWaitingProcessInstanceTasks.forEach((readyOrWaitingBpmnTask) => {
           highlightBpmnIoElement(
             canvas,
-            readyOrWaitingBpmnTaskId,
-            'active-task-highlight'
+            readyOrWaitingBpmnTask,
+            'active-task-highlight',
+            rootElement.id
           );
         });
       }
-      if (completedTasksBpmnIds) {
-        completedTasksBpmnIds.forEach((completedTaskBpmnId) => {
+      if (completedProcessInstanceTasks) {
+        const rootElement = canvas.getRootElement();
+        completedProcessInstanceTasks.forEach((completedTask) => {
           highlightBpmnIoElement(
             canvas,
-            completedTaskBpmnId,
-            'completed-task-highlight'
+            completedTask,
+            'completed-task-highlight',
+            rootElement.id
           );
         });
       }
@@ -484,8 +493,8 @@ export default function ReactDiagramEditor({
     diagramType,
     diagramXML,
     diagramXMLString,
-    readyOrWaitingBpmnTaskIds,
-    completedTasksBpmnIds,
+    readyOrWaitingProcessInstanceTasks,
+    completedProcessInstanceTasks,
     fileName,
     performingXmlUpdates,
     processModelId,
diff --git a/spiffworkflow-frontend/src/components/TasksForMyOpenProcesses.tsx b/spiffworkflow-frontend/src/components/TasksForMyOpenProcesses.tsx
index deb2030e..297f2071 100644
--- a/spiffworkflow-frontend/src/components/TasksForMyOpenProcesses.tsx
+++ b/spiffworkflow-frontend/src/components/TasksForMyOpenProcesses.tsx
@@ -41,7 +41,7 @@ export default function MyOpenProcesses() {
       });
     };
     getTasks();
-    refreshAtInterval(REFRESH_INTERVAL, REFRESH_TIMEOUT, getTasks);
+    return refreshAtInterval(REFRESH_INTERVAL, REFRESH_TIMEOUT, getTasks);
   }, [searchParams]);
 
   const buildTable = () => {
diff --git a/spiffworkflow-frontend/src/components/TasksWaitingForMyGroups.tsx b/spiffworkflow-frontend/src/components/TasksWaitingForMyGroups.tsx
index 565cd4a5..5b05dcd0 100644
--- a/spiffworkflow-frontend/src/components/TasksWaitingForMyGroups.tsx
+++ b/spiffworkflow-frontend/src/components/TasksWaitingForMyGroups.tsx
@@ -41,7 +41,7 @@ export default function TasksWaitingForMyGroups() {
       });
     };
     getTasks();
-    refreshAtInterval(REFRESH_INTERVAL, REFRESH_TIMEOUT, getTasks);
+    return refreshAtInterval(REFRESH_INTERVAL, REFRESH_TIMEOUT, getTasks);
   }, [searchParams]);
 
   const buildTable = () => {
diff --git a/spiffworkflow-frontend/src/helpers.tsx b/spiffworkflow-frontend/src/helpers.tsx
index 6781ada9..0b73e517 100644
--- a/spiffworkflow-frontend/src/helpers.tsx
+++ b/spiffworkflow-frontend/src/helpers.tsx
@@ -208,5 +208,8 @@ export const refreshAtInterval = (
     () => clearInterval(intervalRef),
     timeout * 1000
   );
-  return [intervalRef, timeoutRef];
+  return () => {
+    clearInterval(intervalRef);
+    clearTimeout(timeoutRef);
+  };
 };
diff --git a/spiffworkflow-frontend/src/interfaces.ts b/spiffworkflow-frontend/src/interfaces.ts
index 079e4cdc..6afb1144 100644
--- a/spiffworkflow-frontend/src/interfaces.ts
+++ b/spiffworkflow-frontend/src/interfaces.ts
@@ -11,6 +11,13 @@ export interface RecentProcessModel {
   processModelDisplayName: string;
 }
 
+export interface ProcessInstanceTask {
+  id: string;
+  state: string;
+  process_identifier: string;
+  name: string;
+}
+
 export interface ProcessReference {
   name: string; // The process or decision Display name.
   identifier: string; // The unique id of the process
@@ -39,6 +46,7 @@ export interface ProcessInstance {
   id: number;
   process_model_identifier: string;
   process_model_display_name: string;
+  spiff_step?: number;
 }
 
 export interface MessageCorrelationProperties {
diff --git a/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx b/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx
index 9a0495d1..3e0c2094 100644
--- a/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx
+++ b/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx
@@ -1,6 +1,11 @@
 import { useContext, useEffect, useState } from 'react';
 import Editor from '@monaco-editor/react';
-import { useParams, useNavigate, Link } from 'react-router-dom';
+import {
+  useParams,
+  useNavigate,
+  Link,
+  useSearchParams,
+} from 'react-router-dom';
 import {
   TrashCan,
   StopOutline,
@@ -34,15 +39,21 @@ import {
 import ButtonWithConfirmation from '../components/ButtonWithConfirmation';
 import ErrorContext from '../contexts/ErrorContext';
 import { useUriListForPermissions } from '../hooks/UriListForPermissions';
-import { PermissionsToCheck } from '../interfaces';
+import {
+  PermissionsToCheck,
+  ProcessInstance,
+  ProcessInstanceTask,
+} from '../interfaces';
 import { usePermissionFetcher } from '../hooks/PermissionService';
 
 export default function ProcessInstanceShow() {
   const navigate = useNavigate();
   const params = useParams();
+  const [searchParams] = useSearchParams();
 
-  const [processInstance, setProcessInstance] = useState(null);
-  const [tasks, setTasks] = useState<Array<object> | null>(null);
+  const [processInstance, setProcessInstance] =
+    useState<ProcessInstance | null>(null);
+  const [tasks, setTasks] = useState<ProcessInstanceTask[] | null>(null);
   const [tasksCallHadError, setTasksCallHadError] = useState<boolean>(false);
   const [taskToDisplay, setTaskToDisplay] = useState<object | null>(null);
   const [taskDataToDisplay, setTaskDataToDisplay] = useState<string>('');
@@ -80,8 +91,13 @@ export default function ProcessInstanceShow() {
       const processTaskFailure = () => {
         setTasksCallHadError(true);
       };
+      let queryParams = '';
+      const processIdentifier = searchParams.get('process_identifier');
+      if (processIdentifier) {
+        queryParams = `?process_identifier=${processIdentifier}`;
+      }
       HttpService.makeCallToBackend({
-        path: `/process-instances/${modifiedProcessModelId}/${params.process_instance_id}`,
+        path: `/process-instances/${modifiedProcessModelId}/${params.process_instance_id}${queryParams}`,
         successCallback: setProcessInstance,
       });
       let taskParams = '?all_tasks=true';
@@ -98,7 +114,14 @@ export default function ProcessInstanceShow() {
         setTasksCallHadError(true);
       }
     }
-  }, [params, modifiedProcessModelId, permissionsLoaded, ability, targetUris]);
+  }, [
+    params,
+    modifiedProcessModelId,
+    permissionsLoaded,
+    ability,
+    targetUris,
+    searchParams,
+  ]);
 
   const deleteProcessInstance = () => {
     HttpService.makeCallToBackend({
@@ -140,12 +163,12 @@ export default function ProcessInstanceShow() {
   const getTaskIds = () => {
     const taskIds = { completed: [], readyOrWaiting: [] };
     if (tasks) {
-      tasks.forEach(function getUserTasksElement(task: any) {
+      tasks.forEach(function getUserTasksElement(task: ProcessInstanceTask) {
         if (task.state === 'COMPLETED') {
-          (taskIds.completed as any).push(task.name);
+          (taskIds.completed as any).push(task);
         }
         if (task.state === 'READY' || task.state === 'WAITING') {
-          (taskIds.readyOrWaiting as any).push(task.name);
+          (taskIds.readyOrWaiting as any).push(task);
         }
       });
     }
@@ -175,15 +198,18 @@ export default function ProcessInstanceShow() {
     label: any,
     distance: number
   ) => {
+    const processIdentifier = searchParams.get('process_identifier');
+    let queryParams = '';
+    if (processIdentifier) {
+      queryParams = `?process_identifier=${processIdentifier}`;
+    }
     return (
       <Link
         reloadDocument
         data-qa="process-instance-step-link"
-        to={`/admin/process-instances/${
-          params.process_model_id
-        }/process-instances/${params.process_instance_id}/${
-          currentSpiffStep(processInstanceToUse) + distance
-        }`}
+        to={`/admin/process-instances/${params.process_model_id}/${
+          params.process_instance_id
+        }/${currentSpiffStep(processInstanceToUse) + distance}${queryParams}`}
       >
         {label}
       </Link>
@@ -364,10 +390,15 @@ export default function ProcessInstanceShow() {
     }
   };
 
-  const handleClickedDiagramTask = (shapeElement: any) => {
+  const handleClickedDiagramTask = (
+    shapeElement: any,
+    bpmnRootElement: any
+  ) => {
     if (tasks) {
       const matchingTask: any = tasks.find(
-        (task: any) => task.name === shapeElement.id
+        (task: any) =>
+          task.name === shapeElement.id &&
+          task.process_identifier === bpmnRootElement.id
       );
       if (matchingTask) {
         setTaskToDisplay(matchingTask);
@@ -471,19 +502,28 @@ export default function ProcessInstanceShow() {
       );
     }
 
+    if (task.type === 'Call Activity') {
+      buttons.push(
+        <Link
+          data-qa="go-to-call-activity-result"
+          to={`${window.location.pathname}?process_identifier=${task.call_activity_process_identifier}`}
+          target="_blank"
+        >
+          View Call Activity Diagram
+        </Link>
+      );
+    }
+
     if (canEditTaskData(task)) {
       if (editingTaskData) {
         buttons.push(
-          <Button
-            data-qa="create-script-unit-test-button"
-            onClick={saveTaskData}
-          >
+          <Button data-qa="save-task-data-button" onClick={saveTaskData}>
             Save
           </Button>
         );
         buttons.push(
           <Button
-            data-qa="create-script-unit-test-button"
+            data-qa="cancel-task-data-edit-button"
             onClick={cancelEditingTaskData}
           >
             Cancel
@@ -492,7 +532,7 @@ export default function ProcessInstanceShow() {
       } else {
         buttons.push(
           <Button
-            data-qa="create-script-unit-test-button"
+            data-qa="edit-task-data-button"
             onClick={() => setEditingTaskData(true)}
           >
             Edit
@@ -622,8 +662,8 @@ export default function ProcessInstanceShow() {
           processModelId={processModelId || ''}
           diagramXML={processInstanceToUse.bpmn_xml_file_contents || ''}
           fileName={processInstanceToUse.bpmn_xml_file_contents || ''}
-          readyOrWaitingBpmnTaskIds={taskIds.readyOrWaiting}
-          completedTasksBpmnIds={taskIds.completed}
+          readyOrWaitingProcessInstanceTasks={taskIds.readyOrWaiting}
+          completedProcessInstanceTasks={taskIds.completed}
           diagramType="readonly"
           onElementClick={handleClickedDiagramTask}
         />