Hello,
I created a repl to replicate the issue that I'm having. I created a Filter with a custom editor. For this example, I used a Textbox and I save the changes back to the context.FilterDescriptor.Value in the OnChange method which occurs when the user blurs focus.
If you start the repl w/o checking the Use Custom Editor checkbox and enter text where the "Sample" value is located you will see the changes are saved properly to the bound CompositeFilter property and are echo'd back in the screen.
If instead you check the Use Custom Editor box and perform the same test you'll see that the same changes are not present in the bound CompositeFilter.
Note that this issue only occurs if you start with an existing CompositeFilter and bind it to the filter control. It seems that if the control creates the FilterDescriptor objects then their changes bind properly, but if the FilterDescriptor objects existed before binding to the control then the issue occurs.
https://blazorrepl.telerik.com/wIOtcKOb31mjTc3351
Thank You,
-Andy