Hi!
I tried to select several categories in product module but it doesn't work.
Joomla! 4.2.8 and Virtuemart 4.0.12 10777, PHP 8.0.27.
Multi-cat selection works OK with VM 4.0.12 10777 on J 3.10.11 so it is yet another J4 problem. Thanks for letting us know.
As a workaround you can make multiple copies of the module, each for different cats.
Joomla! 3.10.11 and Virtuemart 4.0.6 10690, PHP 7.4.33 - it doesn't work either. After saving, only the last category is in the field.
Just checked, products from multiple categories are being shown as random products on my J3 test set as I have the category filter turned off - I forgot about this switch. If turned on then as it says in the tooltip, only products from "this category" are shown. ie a single category. I suspect ithas always been this way.
On client sites I only ever used the module in random product mode.
It's a bit strange. The XML file uses the type="vmcategories" field, although type="vmcategory" would be more logical and less misleading. :-\