STEPS TO REPRODUCE
1. Open Spectacle window (press Print)
2. Capture Mode: Rectangular region, Delay: 5s
3. Click "Take a new Screenshot" button
4. Before the delay time is out, open Application Dashboard
The rectangular region appears. But the keyboard is unusable, if you press Enter, Esc, Arrow, Alt, Shift... nothing happens.
The keyboard is usable.
(available in About System)
KDE Plasma Version: 5.14.1
KDE Frameworks Version: 5.51.0
Qt Version: 5.11.2
To exit the screenshot screen, double click on the rectangular region on the screen.
*** This bug has been marked as a duplicate of bug 374009 ***