Sometimes when I'm working with BlueJ, a dialog box appears as an empty grey box rather than containing anything.
For example, occasionally, if I click the "new ObjectName()" button in the class context menu, an empty grey box appears, rather than the normal object creation box. This has happened to all of the dialogs.
I run Ubuntu 8.04, with the jdk1.6.0_07 version JDK.
When it next happens I'll attach a screenshot, but due to sods law you may have to wait a bit.