Could you post print screen ?

print screen:

print screen2:

First, these are not Actions, but Activities. 👿
It is very important for me to know the exact issue to analyse it 😉

Question : how did you delete these Activities ?
(I need to know if you deleted items in database or use an existing funcitonality).

Solution : delete in database line of table planningelement where refName is null.

I want to say.. I didn't not deleate but I closed activities, so with STATE "close", so in existing funtionality. But iI have a réal problem: empty rows.
So I'll try to deleat il in database line..

Thank you very much.

How did you close ?
One by one or with multiple update ?

I closed one by one.