SUMMARY
When I click with the right mouse button on the right side of the timeline on a clip, the menu immediately disappears. Seems that if I would do a left click right after the menu has opened. When I click on the middle of the timeline, the buttons work as expected.
Tried it with two Win10 computers (mouse and touchpad), running kdenlive 19.12.3.
Video of the bug: https://drive.google.com/open?id=1Sa0sgmvhdIEs_PFaeI4ZsO31PxyZzG_V

STEPS TO REPRODUCE
1. Add clips to the timeline.
2. Right mouse click on the clip which is on the right side of the timeline.
3. 

OBSERVED RESULT
The menu opens for a moment, then it disappears.

EXPECTED RESULT
The menu would open, stays opened while I choose an option with the left mouse button.

SOFTWARE/OS VERSIONS
Windows: Win10 current
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Video of the bug: https://drive.google.com/open?id=1Sa0sgmvhdIEs_PFaeI4ZsO31PxyZzG_V