Created attachment 122108 [details]
Demonstration of the panel flicker bug

SUMMARY
I have an auto-hidden panel on the left edge of my screen. When I move the mouse to reveal the panel, the panel flickers for a moment.

STEPS TO REPRODUCE
1. Set up an auto-hidden panel on the left edge of the screen (only happens on the left).
2. Move cursor to left edge of the screen so that it is over the task bar and reveals the panel (not reproducible if it is over the application launcher or configure panel icon)

OBSERVED RESULT
It looks like the cursor moves 1 pixel off the screen, then the panel shows, the cursor is moved 1 pixel to be back on the screen and the panel flickers for a moment.

EXPECTED RESULT
The panel shows without flickering or moving the cursor.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.16.4
KDE Frameworks Version: 5.60.0
Qt Version: 5.13.0
Kernel Version: 5.2.8-arch1-1-ARCH
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-6600K CPU @ 3.50GHz
Memory: 15.5 GiB of RAM 

ADDITIONAL INFORMATION
Nvidia GeForce GTX 980
driver: 430.40-4