I have 2 forms based on CBizObjMaintenanceForm. When I made the change from cdmm2.07 to cbmm3.01 I began getting an error #1924 in cnavbuttons.refresh() when entering form A.

ACTIVEFORM is not an object

SET DATASESSION TO _SCREEN.ActiveForm.DataSessionID

I solved this by changing it to

IF NOT TYPE('_SCREEN.ActiveForm.DataSessionID') = 'U'
SET DATASESSION TO _SCREEN.ActiveForm.DataSessionID
ENDIF

Now I will say that I did not do this with screen B. Screen A begins by calling aCBbaseModalForm in its INIT method so that I can retrieve view parameters. Things seem fine, but I thought I would ask.