Deleting value from Mask: Simple Shape & Mask: From File deletes clip from track

After applying filter, scroll wheel up at least 1 frame in the frame numerical input box.
The click on the numerical value input on the filter, it highlights the whole value at once.
Click either delete or backspace.
The whole clip disappears from the track.
2020-05-07_21-07-01

Shotcut 20.04.12
Windows 10 Home

Good find, and it is very strange that I have to click in the current time field first to trigger it but not Recent search field, Export field, or a timecode field Properties - at least on Linux where I just tested.

This is fixed for the next version 20.06, but now there is a side effect that when you go from this timecode field to any filter field (using the mouse), you cannot edit. This odd behavior is part of the cause of the reported bug. After this change, to workaround the side effect you need to click in the field a second time. Overall the side effect is much less problematic than a surprise destructive (but undoable) operation.