Hello fellow Trados Studio users! I have an odd problem in Studio 2019 where "Edit Source" is grayed out for some segments and not others.

Here are 3 screenshots in the same XLIFF: 2 of them you can edit the source, and the 3rd you cannot.

I thought perhaps it was the tags in the source segment that were preventing me from having the Edit Source option, but the segment I've selected in the 2nd screenshot contains tags. The segment in the 1st screenshot is a List Item, which is also what the problem segment (3rd screenshot) is.

Can anyone please advise?

TIA,

Clara