its a huge problem in Footprints-3D.
Place 3-D model (doesent matter of txpe: step or wrl) - all still ok. But try to correct the placement (Offset/Rotation) lets dissapear the model (even if try to move ti 1mm or less). Model is no more present at all…
By the way, I hardly miss “browse” feature in symbol library for finding right footprint too…
Report this on https://bugs.launchpad.net/kicad, usually they fix critical bugs in a few days (most of the time 2).
KiCad v6 development branch was released a few days, so could be present some bugs. I self reported 2 important ones or more.
If you mean the old Select Footprint button in the Edit Symbols dialog, you can get to that by right-clicking over the footprint’s field’s value in the grid. (Of course there’s also a button when you click in the cell in the latest sources.)
if you go to footprint-lib, just open some footprint to edit, go to properties->3D Settings and try to change Offset/Rotation/Scale the 3-D model just dissapear. Its just away.
Try on your side, please.