This has been an issue for me for some time now, thinking it was just on my end, but logging into another computer to use the animation editor allowed me to find that the checkbox for “Select Invisible Parts” in the settings tab actually does nothing. Highlighting the button tells me that this toggles the ability to select invisible parts or not, but this is what happens when I try to utilize this:
https://gyazo.com/109b2cce5be2498bdc03f70a337abf2e
The part I am trying to select is an invisible hitbox for the hand that basically deals damage, and this is a custom rig using the Custom Character Creator plugin.
Or could it possibly be that I am doing something wrong, or is it truly an issue on my end?