Does anything changed with the group and attribute list does not show up or is it a bug?
Does anyone else having this issue on H21?

Could you submit a bug with your system specs? It works for me in 21.0.467.

Thanks for the feedback.
I just checked on Linux fedora 42 H21 build 440 and it is working but not in windows 11.

I will double check just in case.

mzigaib
I just checked on Linux fedora 42 H21 build 440 and it is working but not in windows 11.

I'm on Win 11, H21.464, NVIDIA 581.15 and it's working for me there

Same here, sometimes it works and then all of a sudden the group & attribute list view no longer appears, but I can still see and select the colored groups in the viewport.

Strangely enough it seems like the invisible list view is somehow still blocking the same space in the viewport as when it's visible, because I can't draw anything in that top right part of the view.

After restarting Houdini it works again in both 21.0.559 and 21.0.512

Win 11 / NVIDIA 591.44