SUMMARY
This is my first bug report, so I hope I give enough information to assist in fixing the issue I found. I tried searching for this bug but did not find any related bug reports. Setting the Position and Size settings to Remember in the Special Application Settings section of the Desktop Folder Settings window causes issues with Application Launcher and the desktop appearance after logging out and logging back in.

STEPS TO REPRODUCE
1. Have the kickoff button on the taskbar set to "Application Launcher"
2. Right click on desktop and select “Configure Desktop”
3. When the "Desktop Folder Settings" window appears, resize and move the window to center of screen
4. Right click on the "Desktop Folder Settings" title bar
6. Select "More Actions" > "Special Application Settings…"
7. In the "Size & Position" tab, check "Position" and set it to "Remember", and check "Size" and set to "Remember"
8. Click "OK" button to save settings

OBSERVED BEHAVIOR
9. Click the kickoff button on the taskbar and the "Application Launcher" will popup in the same position and with the same dimensions as the "Desktop Folder Settings" window
10. Log out and then log back in and the desktop appearance will be messed up

EXPECTED BEHAVIOR
No impact on "Application Launcher" and desktop appearance

TO RESTORE THE DESKTOP TO NORMAL:
1. Right click in the visible desktop area and select “Configure Desktop”
2. When the "Desktop Folder Settings" window appears, right click on title bar and select "More Actions" > "Special Application Settings…"
3. In the "Size & Position" tab, uncheck "Position" and uncheck "Size"
6. Click "OK" button to save settings
7. Log out and then log back in and things should be back to normal

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE Neon 5.15
(available in About System)
KDE Plasma Version: 5.15.0
KDE Frameworks Version: 5.55.0
Qt Version: 5.12.0

Please let me know if I can assist any further.