Add-in stealing focus

[Paul]

I have created an add-in with a non-modal dialog box that is used to
search externally archived emails. It is launched from either a button
on an explorer toolbar for from a menu on the explorer toolbar. It
should not (to my knowledge) interact with items or inspectors at all.
However if my add-in dialog is open and I open an email in an inspector
and click on the view/options menu or if I right click on the item in
the explorer and select options from the pop-up menu, my add-in
captures focus and becomes the active window, hiding the options
dialog.

Does anyone have an idea on why this happens and how to end this
behavior?

Thanks,
Paul