Bug 84353 [typing] Hippie completion fills undo stack
I20050202-0800 Toggling through the lists adds each item to the undo stack and hence Undo (Ctrl+Z) undoes each by each.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaMoveLinesAction.java
* @param offset the offset of the selection
	 * @param length the length of the selection
	 */
	private void selectAndReveal(ITextViewer viewer, int offset, int length) {
		
		viewer.setSelectedRange(offset + length, -length);
		
		StyledText st= viewer.getTextWidget();
		if (st != null)
			st.showSelection(); 
	}
	/**
	 * Displays information in the status line why a line move is not possible
	 */
	private void showStatus() {
		IEditorStatusLine status= (IEditorStatusLine) fSharedState.fEditor.getAdapter(IEditorStatusLine.class);
		if (status == null)
			return;
		status.setMessage(false, JavaEditorMessages.Editor_MoveLines_IllegalMove_status, null);
	}
	/*
	 * @see org.eclipse.ui.texteditor.IUpdate#update()
	 */
	public void update() {
		super.update();
		if (isEnabled())
			setEnabled(canModifyEditor());
	}
}