@Erel,
Just to be sure that it wasn't my fault I did some more checking and I just noticed something weird.
When I run something in rapid debug the watch stuff on my laptop is at the bottom of the screen and not added to the tab control on the bottom right.
And then this behaviour is not happening.
When I drag the window over the log window it is docking it to the tab control.
Then the behaviour starts again.
it's...
log is shown
compile'n run
watch tab gets added
error occurs
watch tab gets remove
last tab gets selected due to the tab remove
missing steps:
store selected tab at compile event
re-select the tab that was stored before the watch tab got added