Allow developers to add their own functions to the list of available functions in the RadExpressionEditor and then pass these functions to the LINQ runtime when the expression tree is built. Add support for custom Categories as well. Scheduled for:
The feature will be available in R1 2019, scheduled for the mid of January 2019.
The demand for this feature is not very high considering how long ago it was added. Still, if it still in our backlog and is reviewed on every planning.
6 years... news? :)
User defined functions (through MethodInfo or Type and method name) and user defined constants will greatly improve this control (beyond RadGridView too).