Created attachment 127728 [details]
Contains a simple Netbeans module illustrating the problem in Netbeans, as well as a simple java class that illustrates this using awt/swing code only.

On a dual screen setup, an IllegalArgumentException can be thrown in Netbeans during following scenario when using jre 1.7 (any version)

- undock a window and move it to the other screen
- dock the window

--> IllegalArgumentException: adding a container to a container on a different GraphicsDevice


This is a bug in java 1.7 and happens when you add a Component to a Container on another graphics device, without explicitly removing the Component from its previous parent.

I've attached a simple Netbeans module that illustrates the problem. When ran, you can create a Canvas by going to Windows -> Canvas. Undocking this Canvas, moving to another screen, and re-docking illustrates the bug.

I've also attached a simple java class that illustrates this is a jre 1.7 bug.

Workaround:

Call component.getParent().remove(component) before calling container.add(component).

This issue does not occur when using java 1.6.