Yes, this is in 5.0.97-beta.42+d8af5b792 and has started one or two beta versions ago. Previously it was possible to select a single one using arrow keys.
Yeah, so both with arrow keys and ctrl+click I can still remove items from triplet, quadruplets, etc., but it won't let me get below 2 items in any way. That's in 5.0.97-beta.42+d8af5b792
That's in 5.0.97-beta.42+d8af5b792
I am having the same problem (I am on : 5.0.97-beta.41+aa7f5289a)
Is it better to report it in Github ?
I can reproduce this, and we'll work on a fix, though it may not be for a few weeks.
(This is a side effect of a major rewrite of the collection and item trees, which is why there've been some tree-related bugs in the last week.)