Gene sets: Selection not cleared

[pavlin-policar]

version master (67c10bd)

Expected behavior
I connect the widget to any data, set the "Gene Sets" selection to "CellMarker" and select a couple of different rows. Now I find that "CellMarker" isn't doing it for me, so I switch over to "Panglao" (deselect cellmarker and select panglao). The indices from before are selected. They should not.

The selection should be remembered based on selected "Gene set", so if I switch from "CellMarker" to "Panglao", each should remember its own selection for that dataset.