events - ActiveX control events aren't raised while calling its methods from an MS Access form's Open event

Question

We have an ActiveX grid control written in VB6. One of its method, Group, used to group rows, raises the AfterAutoGroupRowCreated event so the developer can adjust the look and contents of every group row created during the automatic process of grouping.

When our ActiveX grid is hosted on an MS Access form and we call the Group method while populating the grid in the form's Open event, the AfterAutoGroupRowCreated event isn't triggered. But this event definitely works as expected in other development environments, and even in MS Access if we call Group from the form's Load event.

Is it a well known issue of MS Access, when any events of ActiveX controls aren't triggered while "executing" the Open event, or are we doing something wrong?