The Translation Details pop-up window irritates users. 

Because it pops up when the cursor is on the translation details column - which is often crossed with the cursor, and where the cursor often naturally rests - it pops up when users don't want it, and stays there until they click somewhere else. 

It's also annoying that the pop-up covers the target segment column - it would be better for it to cover the side panel. 

I'd actually question the need for the pop-up at all because all the information it contains is already available in the column or the lookups panel. 

Ideally users would have control over all the pop-ups, but I'm flagging this one specifically because it seems more troublesome than the others (eg the terminology ones) for the reasons above.