Bug 310444 [LinkedResources] Drag and Drop dialogs not disabled when Linked Resources turned off
I20100425-2000 - on the 'Linked Resources' preference page, disable the checkbox => DND groups are still enabled (should be disabled) - click OK - drag a file from the OS to the Package Explorer, Resource Navigator,... => "File Operation" dialog is still shown (should not be shown and just make a copy). Selecting "Link to files" gives an error dialog after I clicked OK. Additional UI problems on the preference page: - groups don't use dialog font - missing vertical gap between checkbox and first DND group: The gap should have the same size as the gap between the second group and the "Path variables..." label. Currently, the visual clustering suggests that the checkbox only applies to the DND groups.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/CopyFilesAndFoldersOperation.java
private URI createRelativePath(URI locationURI, IResource resource) {
		if (relativeVariable == null)
			return locationURI;
		IPath location = URIUtil.toPath(locationURI);
		IPath result;
		try {
			result = URIUtil.toPath(resource.getPathVariableManager().convertToRelative(URIUtil.toURI(location), true, relativeVariable));
		} catch (CoreException e) {
			return locationURI;
		}
		return URIUtil.toURI(result);
	}
	/**
	 * Sets the content of the existing file to the source file content.
	 * 
	 * @param source
	 *            source file to copy
	 * @param existing
	 *            existing file to set the source content in
	 * @param subMonitor
	 *            a progress monitor for showing progress and for cancelation
	 * @throws CoreException
	 *             setContents failed
	 */
	private void copyExisting(IResource source, IResource existing,
			IProgressMonitor subMonitor) throws CoreException {
		IFile existingFile = getFile(existing);
		if (existingFile != null) {
			IFile sourceFile = getFile(source);
			if (sourceFile != null) {