Pretty easy to reproduce (this has been happening to me since 2.1.0). It appears that clicking anywhere in the piano roll up to causes the F key to be triggered and stuck. It resets with a MIDI panic or by losing focus of the plugin window. It also will trigger when transitioning between screens. I’ve tried uninstalling, updating, clearing preferences, with no luck.
If I were to take a guess, there’s a UI bug that makes the plugin think the note is being clicked. One thing I can confirm is that it is not related to external MIDI, as it occurs in both the instrument VSTi as well as the audio effect VST. Both VST2 and VST3 are affected.
System: Windows 10, Ableton 10.1.8, Scaler version 2.1.1 - 2.1.2
Has anyone else seen this? It’s driving me nuts.
Edit: Thought it might be useful to include my resolution, i’m running on a 3440x1440p monitor (Ultrawide) at 100% OS scaling in Windows.