Increment the index after the element was added to the list

Currently elements are merged in reverse order if an insert index is
give because the add is always performed at the original index.

This now do the following:
- on each insert operation the index is incremented if given
- if the index is larger than the list size the element is added
instead.

Author: laeubi

bundles/org.eclipse.e4.ui.model.workbench/src/org/eclipse/e4/ui/model/internal/ModelUtils.java

@@ -197,7 +197,12 @@ private static void mergeList(List<MApplicationElement> list, List<MApplicationE
 				if (index == -1) {
 					list.add(element);
 				} else {
-					list.add(index, element);
+					if (index > list.size()) {
+						list.add(element);
+					} else {
+						list.add(index, element);
+					}
+					index++;
 				}
 			}
 		}