If you open a source file to edit and have the Clipboard toolbar open the cut copy and paste icons become active as expected. You can confirm this by opening the edit menu and seeing the cut copy and paste actions activated.
If however you now close the text file that you were editing the Clipboard toolbar cut and copy icons stay active when they should be grayed out. You can confirm this by once again opening the Edit menu and observe that the cut copy and paste actions are indeed disabled.
If you close the Clipboard toolbar and reopen it without and files open then the toolbar will open to is proper state of the cut, copy, and paste icons disabled.
Broken deep in the API implementation: core-main#2384c335e6b7
Integrated into 'main-golden', will be available in build *201004140201* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)
User: Jaroslav Tulach <firstname.lastname@example.org>
Log: #183316: Deliver PropertyChangeEvent when the action is becoming disabled