I've got a strange problem with my TIA Portal 15.1 installation - I can't delete anything.
Let's say I drag an "assignment" element to a network, I'm unable to remove it afterwards.
Same happens if I add new Functional Block or anything else for that matter, when I press delete key or choose delete from context menu entry, nothing happens.
I'm most likely missing something obvious but just can't figure it out

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Many thanks,
Joanna
