fix(moddle-copy): primitive arrays cloning

Closes https://github.com/bpmn-io/bpmn-js/issues/1518

lib/features/copy-paste/ModdleCopy.js

@@ -234,8 +234,6 @@ ModdleCopy.prototype.copyProperty = function(property, parent, propertyName) {
 
       // copying might NOT be allowed
       if (copiedProperty) {
-        copiedProperty.$parent = parent;
-
         return childProperties.concat(copiedProperty);
       }
 

test/fixtures/json/model/custom.json

@@ -22,6 +22,11 @@
           "name": "value",
           "isAttr": true,
           "type": "String"
+        },
+        {
+          "name": "paths",
+          "type": "String",
+          "isMany": true
         }
       ]
     },

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

@@ -781,6 +781,40 @@ describe('features/copy-paste/ModdleCopy', function() {
 
   });
 
+
+  describe('custom', function() {
+
+    var customPackage = require('../../../fixtures/json/model/custom.json');
+
+    beforeEach(bootstrapModeler(basicXML, {
+      modules: testModules,
+      moddleExtensions: {
+        custom: customPackage
+      }
+    }));
+
+
+    it('should copy arrays of strings', inject(function(moddle, moddleCopy) {
+
+      // given
+      var paths = [ 'A', 'B', 'C' ];
+
+      var customElement = moddle.create('custom:CustomSendElement', {
+        paths: paths
+      });
+
+      // when
+      var newElement = moddleCopy.copyElement(customElement, moddle.create('custom:CustomSendElement'));
+
+      // then
+      expect(newElement.paths).to.have.length(3);
+      expect(newElement.paths).to.eql(paths);
+
+      expectNoAttrs(newElement);
+    }));
+
+  });
+
 });