There is some undesirable behavior that has been discovered by our users regarding APS.Net RadGrid when filtering with the checkbox list.  I have seen that the issue also happens on the Telerik Demo page found here and will use it as the example: https://demos.telerik.com/aspnet-ajax/grid/examples/functionality/filtering/basic-filtering/defaultcs.aspx

If you go to the last demo on that page (Filtering with Client-Side Binding) select the filter for Country.  When the checkbox items appear, click on an item, however do not click on the checkbox.  What happens is the dropdown closes and nothing happens.  The demo however is for cliet side binding which is does not postback to the server.  Our control is handled on the server-side so when this happens a request is sent and the user is presented with the loading circle which makes the user think something is actually happening, yet it is not.

I suggest that the behavior of clicking on an item, outside of the checkbox, checks the box and keeps the list open.

At the least, there should be no request that is sent to the server as the box was not actually checked with the current behavior.

I have attached an image with a red 'X' on where a user may click to reproduce this behavior.