Bug 40772 [plan item] Smart tab on empty lines
When having the caret on an empty line, pressing tab cleans up the line and sets the caret it the right indentation column.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
public boolean isSaveAsAllowed() {
		return true;
	}
	
	/**
	 * The compilation unit editor implementation of this  <code>AbstractTextEditor</code>
	 * method asks the user for the workspace path of a file resource and saves the document
	 * there. See http://dev.eclipse.org/bugs/show_bug.cgi?id=6295
	 */
	protected void performSaveAs(IProgressMonitor progressMonitor) {
		
		Shell shell= getSite().getShell();
		IEditorInput input = getEditorInput();
		
		SaveAsDialog dialog= new SaveAsDialog(shell);
		
		IFile original= (input instanceof IFileEditorInput) ? ((IFileEditorInput) input).getFile() : null;
		if (original != null)
			dialog.setOriginalFile(original);
			
		dialog.create();
		
			
		IDocumentProvider provider= getDocumentProvider();
		if (provider == null) {
			
			return;
		}