SUMMARY
Kickoff (Application Launcher 2.0) type to search regression with multiple instances of Kickoff because of multi-screen usage: No character is being input.

After upgrading to KDE Neon 5.23.0, whenever opening any of the screens application launcher and start typing to search, nothing is happening, no character is appearing in the "Search..." input field at the top of the menu.

STEPS TO REPRODUCE
1. Add one or more "Default Panel" which comes with Kickoff by default as the application launcher on each screen.
2. Open any of the Kickoff instance and use it.
3. Open any other of the Kickoff instances and type directly without clicking in the "Search..." input field at the top.

OBSERVED RESULT
Nothing happens in that other Kickoff instance; no character is appearing in that Kickoff instance "Search..." input.
If you try then clicking in the "Search..." input field and type then you see the characters you are now typing but the search doesn't work.
But if you open the initial Kickoff instance then you see all the characters you typed before and that didn't appear in the second Kickoff instance.

EXPECTED RESULT
In the previous version of KDE neon 5.22.90, whatever Kickoff instance you may have opened, typing directly filled the "Search..." input field and the search was working just fine.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE neon 5.23.0 (user)
KDE Plasma Version: 5.23.0
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.3

ADDITIONAL INFORMATION
Graphics Platform: X11
Screens: 3