Avoid problem that property section for connectors is not shown

* Fixes a problem introduced in during the synchronization of the
  selection of the model editor and the model navigator (in #3084)

Issue-Ref: 3470
Issue-Url: https://af3-developer.fortiss.org/issues/3470



Signed-off-by: Simon Barner <barner@fortiss.org>

org.fortiss.tooling.kernel.ui/src/org/fortiss/tooling/kernel/ui/internal/views/.ratings

@@ -9,4 +9,4 @@ MarkerViewPart.java cbb650271b6877af205421b7cb11f930440a7ef9 GREEN
 NavigatorNewMenu.java a35e391960d1dacbe7f77982e53e1891e9382d5a GREEN
 NavigatorTreeContentComparator.java d9f1354cfdff78b104b28887d2397e5ca0e9755b GREEN
 NavigatorTreeContentProvider.java 1fbe97bebf3805cc1af190cecd784fc1cfd12306 GREEN
-NavigatorViewPart.java a8b1e4e11aedb3fdf80de9ee7c25260abf144201 GREEN
+NavigatorViewPart.java 79872dfaab92f20e8767cff84b66dc9e173601d1 YELLOW

org.fortiss.tooling.kernel.ui/src/org/fortiss/tooling/kernel/ui/internal/views/NavigatorViewPart.java

@@ -300,8 +300,13 @@ public final class NavigatorViewPart extends ViewPart implements ISelectionListe
 	/** {@inheritDoc} */
 	@Override
 	public void selectionChanged(SelectionChangedEvent event) {
+		// Ignore programmatic selection of backup model element
+		if(backupElementToBeSelected != null) {
+			return;
+		}
+
 		IActionService.getInstance().refresh();
-		// Set selection of active editor
+		// Sync selection of active editor with model navigator
 		SelectionUtils.setSelection(getSelectedModelElementList(), false, true);
 
 		// fire upon viewer selection change