if (!container.isReadOnly())
if (container.isAccessible() && !container.isReadOnly())
	public void validateDrop(Object target, DropTargetEvent event, int operation) {		event.detail= DND.DROP_NONE;				boolean isPackageFragment= target instanceof IPackageFragment;		boolean isJavaProject= target instanceof IJavaProject;		boolean isPackageFragmentRoot= target instanceof IPackageFragmentRoot;		boolean isContainer= target instanceof IContainer;				if (!(isPackageFragment || isJavaProject || isPackageFragmentRoot || isContainer)) 			return;					if (isContainer) {			IContainer container= (IContainer)target;			if (!container.isReadOnly())				event.detail= DND.DROP_COPY;		} else {			IJavaElement element= (IJavaElement)target;			if (!element.isReadOnly()) 				event.detail= DND.DROP_COPY;		}					return;		}