One thing you can do until this is added is to create a new StyleSet in AppStylist for EditorControl (all Infragistics editors) and call it something like Focused. Set the background to what you want.

 Then in your code trap the Enter and Leave events of your controls. Set the StyleSetName to "Focused" if it has focus or "" if it does not have focus. This is helpful if your Resolution Order is ApplicationThenControl.

 HTH