Bug 63155 [Refactoring] no user feedback when error during implicit refactoring triggered by drag'n'drop
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/SelectionTransferDropAdapter.java
try{
			switch(event.detail) {
				case DND.DROP_MOVE: handleDropMove(target, event); break;
				case DND.DROP_COPY: handleDropCopy(target, event); break;
				case DND.DROP_LINK: handleDropLink(target, event); break;
			}
		} catch (JavaModelException e){
			ExceptionHandler.handle(e, PackagesMessages.getString("SelectionTransferDropAdapter.error.title"), PackagesMessages.getString("SelectionTransferDropAdapter.error.message")); 
		} catch(InvocationTargetException e) {
			ExceptionHandler.handle(e, RefactoringMessages.getString("OpenRefactoringWizardAction.refactoring"), RefactoringMessages.getString("OpenRefactoringWizardAction.exception")); 
		} catch (InterruptedException e) {
			
		}	finally{
			
			
			
			event.detail= DND.DROP_NONE;
		}
	}
	
	private int handleValidateDefault(Object target, DropTargetEvent event) throws JavaModelException{
		if (target == null)
			return DND.DROP_NONE;
			
		return handleValidateMove(target, event);	
	}
	
	private int handleValidateMove(Object target, DropTargetEvent event) throws JavaModelException{
		if (target == null)
			return DND.DROP_NONE;