I have used the following instructions to create a drive down list in the 'value relation' widget to allow a category to be selected in one attribute which filters the options in another. This has worked, however only selections in one category can then be made even though 'allow multiple selections' is checked. If selections are made from a second category the ones selected from the original category disappear. I need to be able to select options from several categories. Is this possible?
https://www.northrivergeographic.com/qgis-3-2-drive-down-lists-aka-value-relation-widget/
QGIS 3.34.1
