fix(copy-paste): copy attacher properties

Closes #1190

lib/features/copy-paste/BpmnCopyPaste.js

@@ -84,17 +84,26 @@ export default function BpmnCopyPaste(bpmnFactory, eventBus, moddleCopy) {
 
   var references;
 
-  function resolveReferences(descriptor) {
+  function resolveReferences(descriptor, cache) {
     var businessObject = getBusinessObject(descriptor);
 
     // default sequence flows
     if (descriptor.default) {
+
+      // relationship cannot be resolved immediately
       references[ descriptor.default ] = {
         element: businessObject,
         property: 'default'
       };
     }
 
+    // boundary events
+    if (descriptor.host) {
+
+      // relationship can be resolved immediately
+      getBusinessObject(descriptor).attachedToRef = getBusinessObject(cache[ descriptor.host ]);
+    }
+
     references = omit(references, reduce(references, function(array, reference, key) {
       var element = reference.element,
           property = reference.property;
@@ -134,7 +143,7 @@ export default function BpmnCopyPaste(bpmnFactory, eventBus, moddleCopy) {
     );
 
     // resolve references e.g. default sequence flow
-    resolveReferences(descriptor);
+    resolveReferences(descriptor, cache);
 
     copyProperties(descriptor, newBusinessObject, [
       'isExpanded',

test/spec/features/copy-paste/BpmnCopyPasteSpec.js

@@ -167,6 +167,38 @@ describe('features/copy-paste', function() {
       );
 
 
+      it('should copy attacher properties', inject(function(canvas, copyPaste, elementRegistry) {
+
+        // given
+        var task = elementRegistry.get('Task_1'),
+            boundaryEvent = elementRegistry.get('BoundaryEvent_1'),
+            rootElement = canvas.getRootElement();
+
+        // when
+        copyPaste.copy([ task, boundaryEvent ]);
+
+        var elements = copyPaste.paste({
+          element: rootElement,
+          point: {
+            x: 1000,
+            y: 1000
+          }
+        });
+
+        // then
+        task = find(elements, function(element) {
+          return is(element, 'bpmn:Task');
+        });
+
+        boundaryEvent = find(elements, function(element) {
+          return is(element, 'bpmn:BoundaryEvent');
+        });
+
+        // then
+        expect(getBusinessObject(boundaryEvent).attachedToRef).to.equal(getBusinessObject(task));
+      }));
+
+
       it('should copy loop characteristics porperties',
         inject(function(canvas, copyPaste, elementRegistry, modeling) {