to reproduce:
1.) download & extract XnView MP 0.39
2.) Create an 'xnview.ini' in the same extracted program folder(s)
3.) Run the program, and "Import Clipboard" an image
4.) Draw Spotlight and press apply, to apply the spotlight
5.) Now press Ctrl+Z on the image to undo the entire spotlight

6.) Spotlight is undone from picture...However 'Spotlight' tool is now Greyed Out
So in this instance, immediately after pressing the Ctrl+Z Undo command, the Spotlight needs to detect this and not get greyed out.
Spotlight tool, I believe, should only ever remain 'greyed out' during spotlight mode or after the user has applied the spoltight or in other miscelleneos cases such as animated files or special non-edit images....It should not grey out after pressing the Ctrl+Z (program's Undo).
I am not meaning the separate toolbar 'undo' of spotlight toolbar
