diff --git a/lib/import/BpmnImporter.js b/lib/import/BpmnImporter.js
index db0d86ce..4b13cbe7 100644
--- a/lib/import/BpmnImporter.js
+++ b/lib/import/BpmnImporter.js
@@ -108,7 +108,11 @@ BpmnImporter.prototype.add = function(semantic, di, parentElement) {
     // add a virtual element (not being drawn)
     element = this._elementFactory.createRoot(elementData(semantic, di));
 
-    this._canvas.setRootElement(element);
+    if (is(semantic, 'bpmn:SubProcess')) {
+      element.id = element.id + '_plane';
+    }
+
+    this._canvas.createPlane(semantic.id, element);
   }
 
   // SHAPE
@@ -144,7 +148,7 @@ BpmnImporter.prototype.add = function(semantic, di, parentElement) {
 
       // check whether data store is inside our outside of its semantic parent
       if (!isPointInsideBBox(parentElement, getMid(bounds))) {
-        parentElement = this._canvas.getRootElement();
+        parentElement = this._canvas.findPlane(parentElement).rootElement;
       }
     }
 
@@ -172,7 +176,7 @@ BpmnImporter.prototype.add = function(semantic, di, parentElement) {
       // are rendered correctly across different "hacks" people
       // love to model such as cross participant / sub process
       // associations
-      parentElement = null;
+      parentElement = this._canvas.findPlane(parentElement).rootElement;
     }
 
     // insert sequence flows behind other flow nodes (cf. #727)
diff --git a/lib/import/BpmnTreeWalker.js b/lib/import/BpmnTreeWalker.js
index 214d5191..760f028a 100644
--- a/lib/import/BpmnTreeWalker.js
+++ b/lib/import/BpmnTreeWalker.js
@@ -216,7 +216,7 @@ export default function BpmnTreeWalker(handler, translate) {
 
     var ctx = visitRoot(rootElement, plane);
 
-    if (is(rootElement, 'bpmn:Process')) {
+    if (is(rootElement, 'bpmn:Process') || is(rootElement, 'bpmn:SubProcess')) {
       handleProcess(rootElement, ctx);
     } else if (is(rootElement, 'bpmn:Collaboration')) {
       handleCollaboration(rootElement, ctx);
diff --git a/lib/import/Importer.js b/lib/import/Importer.js
index 7434f220..fdde1f4f 100644
--- a/lib/import/Importer.js
+++ b/lib/import/Importer.js
@@ -33,7 +33,8 @@ export function importBpmnDiagram(diagram, definitions, bpmnDiagram) {
 
   var importer,
       eventBus,
-      translate;
+      translate,
+      canvas;
 
   var error,
       warnings = [];
@@ -66,7 +67,16 @@ export function importBpmnDiagram(diagram, definitions, bpmnDiagram) {
 
     // traverse BPMN 2.0 document model,
     // starting at definitions
-    walker.handleDefinitions(definitions, bpmnDiagram);
+    if (!bpmnDiagram && definitions.diagrams) {
+      for (var i = 0; i < definitions.diagrams.length; i++) {
+        walker.handleDefinitions(definitions, definitions.diagrams[i]);
+      }
+    } else {
+      walker.handleDefinitions(definitions, bpmnDiagram);
+    }
+
+    var mainDiagram = bpmnDiagram || definitions.diagrams[0];
+    canvas.setActivePlane(mainDiagram.plane.bpmnElement.id);
   }
 
   return new Promise(function(resolve, reject) {
@@ -74,6 +84,7 @@ export function importBpmnDiagram(diagram, definitions, bpmnDiagram) {
       importer = diagram.get('bpmnImporter');
       eventBus = diagram.get('eventBus');
       translate = diagram.get('translate');
+      canvas = diagram.get('canvas');
 
       eventBus.fire('import.render.start', { definitions: definitions });
 
diff --git a/lib/util/DiUtil.js b/lib/util/DiUtil.js
index 0bde14d7..b35db883 100644
--- a/lib/util/DiUtil.js
+++ b/lib/util/DiUtil.js
@@ -18,6 +18,10 @@ export function isExpanded(element, di) {
   if (is(element, 'bpmn:SubProcess')) {
     di = di || getDi(element);
 
+    if (di && is(di, 'bpmndi:BPMNPlane')) {
+      return true;
+    }
+
     return di && !!di.isExpanded;
   }
 
diff --git a/test/fixtures/bpmn/import/collapsed-subprocess.bpmn b/test/fixtures/bpmn/import/collapsed-subprocess.bpmn
new file mode 100644
index 00000000..e6ffbc95
--- /dev/null
+++ b/test/fixtures/bpmn/import/collapsed-subprocess.bpmn
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_0og86p5" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="4.8.0" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.15.0">
+  <bpmn:process id="Process_1rjrv55" isExecutable="true">
+    <bpmn:subProcess id="Subprocess" name="SubProcess">
+      <bpmn:task id="Task_B" name="TaskB" />
+    </bpmn:subProcess>
+    <bpmn:task id="Task_A" name="TaskA" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1rjrv55">
+      <bpmndi:BPMNShape id="Activity_0ndhgel_di" bpmnElement="Subprocess" isExpanded="false">
+        <dc:Bounds x="160" y="77" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Activity_0annkr0_di" bpmnElement="Task_A">
+        <dc:Bounds x="290" y="77" width="100" height="80" />
+      </bpmndi:BPMNShape>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_2">
+    <bpmndi:BPMNPlane id="BPMNPlane_2" bpmnElement="Subprocess">
+      <bpmndi:BPMNShape id="Activity_16df75v_di" bpmnElement="Task_B">
+        <dc:Bounds x="420" y="77" width="100" height="80" />
+      </bpmndi:BPMNShape>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>
diff --git a/test/spec/import/ImporterSpec.js b/test/spec/import/ImporterSpec.js
index aef20379..ed16d261 100644
--- a/test/spec/import/ImporterSpec.js
+++ b/test/spec/import/ImporterSpec.js
@@ -665,6 +665,71 @@ describe('import - Importer', function() {
 
   });
 
+
+  describe('Multiple Planes', function() {
+
+    it('should import multiple diagrams', function() {
+
+      // given
+      var xml = require('../../fixtures/bpmn/multiple-diagrams.bpmn');
+
+      // when
+      return runImport(diagram, xml).then(function(result) {
+
+        var warnings = result.warnings;
+
+        // then
+        expect(warnings).to.have.length(0);
+
+        expect(diagram.get('elementRegistry').get('Task_A')).to.exist;
+        expect(diagram.get('elementRegistry').get('Task_B')).to.exist;
+      });
+    });
+
+
+    it('should allow subProcess to have attached plane', function() {
+
+      // given
+      var xml = require('../../fixtures/bpmn/import/collapsed-subprocess.bpmn');
+
+      // when
+      return runImport(diagram, xml).then(function(result) {
+
+        var warnings = result.warnings;
+
+        // then
+        expect(warnings).to.have.length(0);
+
+        expect(diagram.get('elementRegistry').get('Subprocess')).to.exist;
+        expect(diagram.get('elementRegistry').get('Subprocess_plane')).to.exist;
+      });
+    });
+
+
+    it('should render Tasks on different layers', function() {
+
+      // given
+      var xml = require('../../fixtures/bpmn/multiple-diagrams.bpmn');
+
+      // when
+      return runImport(diagram, xml).then(function() {
+
+        var elementRegistry = diagram.get('elementRegistry'),
+            canvas = diagram.get('canvas'),
+            taskA = elementRegistry.get('Task_A'),
+            taskB = elementRegistry.get('Task_B');
+
+        var activePlane = canvas.getActivePlane(),
+            planeA = canvas.findPlane(taskA),
+            planeB = canvas.findPlane(taskB);
+
+        // then
+        expect(activePlane).to.eql(planeA);
+        expect(planeA).to.not.eql(planeB);
+      });
+    });
+
+  });
 });