Bug 14228 Too easy to create duplicate methods
Build 20020418 - I was browsing some source (not even actively editing). - Suddenly I noticed there was a squiggle on one of the constructors. - Hover told me that there were two methods (sp) with the same name. - Scrolled down to see that, in fact, I did have another copy of the constructor. Strange. How did this ever compile? - It turns out I must have inadvertently dragged the constructor a little bit in the Outline. - With the new DnD support in the Outline, it is far too easy to create duplicates.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/SelectionTransferDropAdapter.java
return DND.DROP_NONE;
		
		if (canPasteSourceReferences(target, event))
			return DND.DROP_COPY; 
		
		if (fMoveRefactoring == null){
			fMoveRefactoring= new MoveRefactoring(fElements, JavaPreferencesSettings.getCodeGenerationSettings());
		}	
		
		if (!canMoveElements())
			return DND.DROP_NONE;	
		
		if (fMoveRefactoring.isValidDestination(target))
			return DND.DROP_MOVE;
		else
			return DND.DROP_NONE;	
	}
	
	private boolean canMoveElements() {
		if (fCanMoveElements == 0) {
			fCanMoveElements= 2;
			if (! canActivate(fMoveRefactoring))
				fCanMoveElements= 1;
		}
		return fCanMoveElements == 2;
	}
	
	private boolean canActivate(ReorgRefactoring ref){
		try{
			return ref.checkActivation(new NullProgressMonitor()).isOK();