NetBeans IDE comes with a very hand visual editor for designing Forms and Dialogs, called the “GUI Builder“. One of the features I like the most is the ability to snap components relative to another component’s position or relative to the container component’s edges, etc. However, if you work on a complex form with many different components around it is possible that things may get confusing regarding what is snapping where.
To work this around the GUI Builder provides the GUI Builder Assistant. This is the white box with the bulb icon on the left. During snapping this box gives enlightening information about how the moving component will be positioned, by displaying messages like: “Snap at the preferred distant from the container’s left border”, “Snap at the small preferred distance from a component above”, etc.
This GUI Builder Assistant tool comes with a close (‘X’) icon which allows you to easily hide it if you don’t need it. But if you accidentally clicked the close icon, it may be confusing to restore the assistant back. To do so, you have to go to the Tools menu and open Options dialog. From there go to the Java section, the select the GUI Builder tab, and make sure that you check the Show Assistant checkbox.
(In a pinch, you have to go to: Tools -> Options -> Java -> GUI Builder -> Show Assistant).
I hope this helps!