I´m trying to set focus to a grind when a Button is pushed. But I always get a error:

Nummer: 2012
Meddelande: Cannot call SetFocus from within a When, Valid, RangeHigh or RangeLow event.
Radnummer: 3
Text: THISFORM.GRResultat.SetFocus()
Metod: CLICK
Object: FRMSOKKLIENT.COMMAND4
Module: FRMSOKKLIENT.SCT


Is there any one how have an idea whats to do?