Created attachment 125946 [details]
Screenshot with the button not visible (should have been above bottom panel)

SUMMARY


STEPS TO REPRODUCE
1. Have a panel on the e.g. left hand side of your monitor.
2. Try to configure the panel in it's behaviour (e.g. auto-hide)
3. Do not find the button for accessing these options, because it's under the bottom panel/out of reach

OBSERVED RESULT
Configuration button inaccessible.

EXPECTED RESULT
Configuration button accessible (as it was in 5.17.x)

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.18
KDE Plasma Version: 5.18.0
KDE Frameworks Version: 5.67.0
Qt Version: 5.13.2
Kernel Version: 4.15.0-76-generic
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-6500TE CPU @ 2.30GHz
Memory: 15,5 GiB

ADDITIONAL INFORMATION
I have a Screenshot attached.