Unable to move tracks & plugins

I’ve been running into an issue where I suddenly lose the ability to move tracks (rearrange their order in Project Window) or move plugins to other tracks via drag & drop. It seems to be pretty random but today it happened right after creating a new project. The first time it happened in the middle of a longer session. I usually have to exit Cubase to fix it, but the first time I alt-tabbed out for a while and then it suddenly started working again.

Feels like a bug, anybody else had the same?