For dropdown filter widgets, it would be great if there is an 'is empty' option, showing objects where the association is not filled.
I totally agree, adding an 'is empty' option in the dropdown filter would be really helpful, especially for large datasets. Sorting isn't the best solution, and this feature would make working with associations much easier. I hope Mendix can add this without making things slower.
This is very expensive to support unless Mendix changes the underlying way that associations are stored.
is there any workaround for having empty as an option in dropdown for datagrid2 other than sorting?
Yes please. Sorting works to some degree, but obviously that's not very handy when it's about large data sets.