After latest updates, there is an invisible dead zone at the top.
No interaction is possible (any mouse button) while hovering. On mouse over, the cursor icon changes the theme from Breath to Adwaita.
It’s 3px in height, but doesn’t span the whole width (outermost corners are not affected).
Screen capture demonstrating this issue
I didn’t change the configuration recently, beside updating the system.
Any idea how to track this down?