Bug 29711 Move refactoring doesn't honor read-only flags
Build I20030115 - JUnit setup - create TestCase.java in junit.runner - make it read-only - move TestCase from framework to runner - answer yes to override observe: the file in runner gets replaced althouh it is read-only
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/SelectionTransferDropAdapter.java
return;
	}
	
	private int handleValidateCopy(Object target, DropTargetEvent event) throws JavaModelException{
		if (canPasteSourceReferences(target))
			return DND.DROP_COPY;
		
		if (fCopyRefactoring == null){
			IPackageFragmentRootManipulationQuery query= JdtCopyAction.createUpdateClasspathQuery(getViewer().getControl().getShell());
			fCopyRefactoring= new CopyRefactoring(fElements, new CopyQueries(), query);
		}
		
		if (!canCopyElements())
			return DND.DROP_NONE;	
		if (fCopyRefactoring.isValidDestination(target))
			return DND.DROP_COPY;
		else
			return DND.DROP_NONE;					
	}
	private boolean canMoveSelectedSourceReferences(Object target) throws JavaModelException{
		ICompilationUnit targetCu= getCompilationUnit(target);
		if (targetCu == null)
			return false;
			
		ISourceReference[] elements= getDragableSourceReferences();		
		for (int i= 0; i < elements.length; i++) {
			if (targetCu.equals(SourceReferenceUtil.getCompilationUnit(elements[i])))	
				return false;
		}
		return true;