Thank you!!This might be related to the second to last point from the notes in the OP, if Windows sees the skin as a full screen application. You could try adjusting the bottom rectangle Shapes' coordinates and / or size in HotCorners.ini and see if that makes a difference, for example using the work area variables instead of the screen area ones (not sure whether the autohidden taskbar changes the size of the 'screen' area or not):
https://docs.rainmeter.net/manual/variables/built-in-variables/#MonitorVariables
Generally speaking, the taskbar wouldn't act as it should on hover if it was 'covered' by some other window (possibly the skin in this case). Either this or the skin size could be the culprit for what you experience.
Additional references, that deal with most of the skin code:
https://docs.rainmeter.net/manual/meters/shape/#Rectangle
https://docs.rainmeter.net/manual/mouse-actions/
https://docs.rainmeter.net/manual/bangs/#MouseAction
To be honest, I am not a programmer and do not know how to code, I just know the basics and the necessary knowledge for an outsider but I will try, using the links kindly provided by you, to educate myself on the matter and try to resolve the issue.
I will keep you updated on how it's going.
Statistics: Posted by JustMoney1 — Today, 1:01 am