This Bugzilla instance is a read-only archive of historic NetBeans bug reports. To report a bug in NetBeans please follow the project's instructions for reporting issues.
After select existing Project Group I see error (see screenshot). But after close this error wirndow i select this Project Group - all work well.
Created attachment 91057 [details] Bug on open project group in project explorer
Hi Anton, This is not error, it is notification and advice message. On some systems and configurations (including yours it seems), project chooser dialog is slow because of bug in JDK. NetBeans has just recognized dialog slowness and message offers things to try to get rid of the slowness. You can use the advice or let it be, choice is yours. Original bug is 109703.