What a dummy! I completely forgot the acDialog. I'm so used to mainframe and PC C++ apps where such things are unneeded. Anyway, with code now properly suspended at the call, all is well.

Private Sub tbBoxDescription_DblClick(Cancel As Integer)
DoCmd.OpenForm "frmColorChart", , , , , acDialog, Me.BoxID
End Sub
I do think it would have occurred to me to consolidate the field setting when I returned to the code to add the typical error handling in frmColorChart and elsewhere.

I also couldn't get the SelLength to work nor could I get SelStart = Len(Me.tbBoxDescription.Text) to put the cursor at the end of the string.

Thanks June7.