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
try {
			
			provider.aboutToChange(newInput);
			new ProgressMonitorDialog(shell).run(false, true, op);
			success= true;
			
		} catch (InterruptedException x) {
		} catch (InvocationTargetException x) {
			
			Throwable t= x.getTargetException();
			if (t instanceof CoreException) {
				CoreException cx= (CoreException) t;
				ErrorDialog.openError(shell, JavaEditorMessages.getString("CompilationUnitEditor.error.saving.title2"), JavaEditorMessages.getString("CompilationUnitEditor.error.saving.message2"), cx.getStatus()); 
			} else {
				MessageDialog.openError(shell, JavaEditorMessages.getString("CompilationUnitEditor.error.saving.title3"), JavaEditorMessages.getString("CompilationUnitEditor.error.saving.message3") + t.getMessage()); 
			}
						
		} finally {
			provider.changed(newInput);
			if (success)
				setInput(newInput);
		}
		
		if (progressMonitor != null)
			progressMonitor.setCanceled(!success);
	}
	
	/*
	 * @see AbstractTextEditor#doSetInput(IEditorInput)
	 */