1. Create a new project with RadGridView. 2. Bind it. 3. Add some filter descriptors. 4. Handle the CustomFiltering event and add custom filter for some column. 5. Run the project and you will see that all other filters are not applied.
Custom filtering has a higher priority than regular filtering with FilterDescriptors or the filtering row. If you want the default filtering to be applied to a row you should set the Handled property of the CustomFiltering event arguments to false (the default value is true). See more on this topic in our online documentation - http://www.telerik.com/help/winforms/gridview-filtering-custom-filtering.html