I just encountered the following bug:
If actors are grouped, they are not visible when the option “Show only selected” is selected.
A normal selection of actors:
When I choose “Show only selected” from the context menu, it works as expected:
However, when the actors are grouped, like this:
I get this result:
When you group them after you toggle visibility, they are grouped and visible, but any change to the visibility, back and, forth, makes them disappear again.
Its a real pain, ungrouping actors before isolating them in the viewport…