Just downloaded and launched NB 6.8M2, opened some maven projects i had. One of them (webclient, in the picture) was
showing a yellow triangle badge. By clicking on "Resolve Problems..." from the right-click on project webclient, I got
an unresponsive interface and had to kill it from Task Manager in Windows.
At that point, nothing responded anymore: clicking any buttons in the screen (see attached picture) will produce no action.
However, all windows seemed to paint fine, because you could move both the main NB window and the dialog independently
just fine. You could also resize the main window, which was repainting fine. By resizing the dialog however was not
repainting correctly: was showing overlapping of blue borders (see bottom of attachment).
All this happened just after launching NetBeans and opening projects, so, NetBeans was still scanning projects while
clicking on "Show and Resolve Problems...". The scanning project task also froze (stopped showing progress).