I always thought this was just me so didn’t report it (until recently as it’s gotten worse for me). I’ve had the issue throughout 3 and into all versions of 4. For me, it’s happening very frequently - like every few clicks of edit within design view - so I find I’m forced to use editor now.
I reported here: UI becomes unresponsive after editing elements in visual designer (video included)
@George perhaps this can be merged and prioritised?