Bug 31957 Refactor/move doesn't remember non-java files
When refactoring with "rename", the list of non-java files is remembered from use to use. When using "move", the previous settings are ignored, and the last "rename" settings are used. This is based on the M5 build.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/SelectionTransferDropAdapter.java
private static final int DROP_TIME_DIFF_TRESHOLD= 150;
	public SelectionTransferDropAdapter(StructuredViewer viewer) {
		super(viewer, DND.FEEDBACK_SCROLL | DND.FEEDBACK_EXPAND);
		fAddMethodStubAction= new AddMethodStubAction();
	}
	
	
	public Transfer getTransfer() {
		return LocalSelectionTransfer.getInstance();
	}
	
	
	public void dragEnter(DropTargetEvent event) {
		clear();
		super.dragEnter(event);
	}
	
	public void dragLeave(DropTargetEvent event) {
		clear();
		super.dragLeave(event);
	}
	
	private void clear() {
		fElements= null;
		fSelection= null;
		fMoveRefactoring= null;
		fCanMoveElements= 0;
		fCopyRefactoring= null;
		fCanCopyElements= 0;
	}