DrJava suffers from an incompatibility between the Linux window manager Compiz and Oracle's Swing Java GUI library. We, the developers of DrJava, cannot do anything to fix this problem. We hope that future versions of Java and Compiz will address the incompatibility. In the meantime, we recommend that you disable Compiz if you experience problems. We also suggest that you use the latest versions of Compiz and Java, so you can benefit from possible bug fixes made by Oracle and the Compiz developers. For more information, see http://drjava.org/compiz/.
When DrJava detects that you are using Compiz, it will display the "Compiz Detected" dialog at startup and ask if you want to start DrJava nonetheless. The dialog has three buttons.
Yes. Start DrJava, even though Compiz is being used.
Yes, and ignore from now on. Start DrJava, and never complain about Compiz again.
No. Do not start DrJava.
Whether DrJava should display this warning can be changed by opening the Preferences window and selecting the "Notifications" pane (see Configuring DrJava).