Displaying VB6 form in vbModal mode from CommandBarButton on MS Wo

[Nam]

I have created a COM Add-in for MS Word using VB6. Add-in creates a dropdown
menu when Word opens. When user clicks on a commandBarButton of the menu, a
VB6 forms is displayed. I am able to show the form in a Modeless mode. I want
the user to close the form either by clicking on OK or Cancel button before
opening any other form or using MS Word document. But when I try to display
the form in modal mode (Form1.Show vbModal), the form acts weird; either I
see a portion of the form or I don’t see the form at all.

Environment: Windows XP SP2, MS Word 2000 SP3, VB6 SP5

Could someone please advise me as to how I can successfully perform the
above task?

Thanks in advance,
Nam