Watch out for Blockly Fragments when you replace blocks

I am really enjoying Blockly in Rules. I have been slowly converting my Rules files, most of which I created in OpenHAB 2.x when I was first learning. I’m currently using OpenHAB 3.3M1 on a Pi4B running openhabian, but I doubt the platform matters in this case.

I have on more than on occasion had a rule fail that looked like it should work:

2022-03-28 21:46:05.551 [ERROR] [e.automation.internal.RuleEngineImpl] - Failed to execute rule 'KathleenPresenceConflictTimerStart': Fail to execute action: 3

By moving the Blockly elements around, I stumbled across some Blockly fragments that had slipped behind the main block. I think this happens when I attach a new block where there was already one. It makes sense that it doesn’t just delete the replaced information. But it would be better if it moved if clearly away from the other blocks. (I don’t doubt that the primary problem is that I’m still learning, but I suspect others will get surprised by this, so I’m sharing my experience.).