FWIW: I was working on this same app yesterday and added a new variable but hadn't used it yet. When the debugger got to the line where I assigned a value to it, I lost the yellow bar (debug quit working). I saw the warning about the variable not being used (and there were no other warnings or errors), so I added a line using it and next time I ran the app and debug got to that line, it kept working.
Hello @Erel
This happened to me two days ago. I've had no debugging during coding a widget that I've been working on since Saturday. I was using B4A-Bridge and even though the bridge is working perfect, the debugging suddenly stopped.
So today I thought that I would try USB debugging which worked a treat. I tried everything, I moved subs, recreated modules the lot, nothing worked.
Anyway, I just thought that I would let you know that B4A-Bridge is not working with my current pretty basic widget, I'm stuck using USB debugging fo now