I noticed that when I randomly select some particles/points in a group node, and then want to select the group in a pop-color node inside a pop solver, sometimes I can see and select the group with the drop-down menu, and sometimes there’s no group at all in the drop down menu, and I have to manually type the name in the input field.

This seems to happen randomly, when I add a new pop-color node, the groups are sometimes suddenly appearing in the drop down, and sometimes not.
When I try to check if Houdini sees the group by adjusting the color of the selected points, this also randomly seems to work or not.

I don’t have a clue why this is happening. Is this a bug ?

it depends on whether the group exists on the geometry that that menu queries
it's very likely that inside of the DOPs the group is not present on the geo if you just added it outside of DOPs until you recache

(however in SOPs it can also happen that menu doesn't contain groups or attributes if the node that menu queries hasn't been cooked yet, usually happens if you are opening menu on the node that's not even displayed and it's input is already unloaded from memory, but I assume you are experiencing the former case)

Hey, thanks.

That's what I thought as well, but even when there's no points added to the group ( random selection = 0 ) and I add a new sop-color node I can sometimes see the group name in the drop down, but not in the "old" pop-color node that was already there.

Also I tried to get an Alpha gradient in the pop-color working without succes in the render for a while. Then I created a new pop-color node with exactly the same settings, and suddenly all was fine. As if it was broken...

Very strange.