I use two monitors with different resolutions in the environment below. When I start my DAW and open Sumu in monitor "A", then drag the Sumu window into monitor "B", the mouse no longer tracks correctly. For example, If I drag the mouse over a knob, some other part of the UI responds as if the mouse is dragging there instead. It's as if the mouse tracking is based on the resolution of the monitor it started in. Unfortunately, my monitors don't have a supported resolution in common, so I can only test with them at different resolutions.
When I drag the window back to the original monitor, mouse tracking works again. The same problem happens if I start the DAW and Sumu in Monitor "B" and drag Sumu to monitor "A".
Version 1.0.0b20 (VST3, Arm)
Mac (2021 MacBook Pro 16-inch, Sonoma 14.6.1), using resolution 1728x1117
Recreated in both Bitwig and Reaper, most recent versions
MacBook Pro
Second monitor: BenQ GW2780, using resolution 1920x1080
Interesting, I thought I had fixed all related issues. But it's a new UI framework so I'm not totally surprised. Thank you for the solid report, I'll try to reproduce ASAP.
(also thanks for your patience, I've been off on a much-needed camping break for a bit.)