I've noticed some odd behaviour with a RadGridView in a project of mine-
Basically the grid is built at runtime as the data is provided by a stored proc that can vary the number of rows/columns depending on parameters.
As such, to correctly create a checkboxcolumn for "bit" type data, on Databind, I locate columns with bit data and instantiate GridViewCheckBoxColumns to replace them. This works as expected and populates the checkboxes appropriately, so so far so happy.
The odd thing I noticed after implementing various bits of logic on the ValueChanged ValueChanging cell, and while fiddling around with right-clicking on the grid (context menus etc) was that if you right click on the checkbox cell, a context menu appears as expected, but if you right click on the actual check-box element, sometimes the check toggles, but most mysteriously without firing the ValueChanged or ValueChanging event... !
I'm pretty sure it's not something I've done, so may be worth investigating?
I unfortunately don't yet know enough about C# or your internal object structure to be able to work around this particular issue