Excel VBA

[Rich]

Excel 2000 & 2002
Windows XP operating system.

Problem:
A GUI app was written in VBA using the Next/Back button convention.

When the app is open (VBA app 1) and I open any other Excel app
directly from a file manager (Excel app 2), I cannot see Excel app 2
as a separate app. Excel app 2's name appears on the title banner of
VBA app 1. The contents of Excel app 2 dispays in a spreadsheet behind
the GUI form of VBA app 1. However, the windows app tool bar displays
2 different Excel apps are open.

This does NOT happen when I open the VBA app 1, open Excel, and then
open Excel app 2 from within Excel. The Windows app tool bar displays
both apps and each app displays separately when selected.

It seems that when the VBA app 1 is open and a second Excel app is
opened directly by double clicking on it from a Windows file browser
that Excel app 2 displays on top of/within VBA app 1. The contents of
Excel app 2 dispays in a spreadsheet behind the GUI form of VBA app 1.

What can I do in the VBA code to make any other Excel app display
separtely as it does when Excel is opened first and then a second
Excel file is opened within Excel.