The methods outlined in my question are a correct way to enable this feature.
The issue I ran into is that a custom filter that had been written by another developer was dynamically generating an XML string and setting it to the GridName property of the UniView control.
This was overriding any of the methods above, resulting in the behavior I was struggling with.
So from a troubleshooting perspective:
- Look at the
UniGrid in the code-in-front to see if <GridOptions ShowSelection="true"/> has been defined.
- Look in the code-behind and see if the
GridOptions are defined in the Page_Load method
- Look to see if the
GridName property is being set anywhere