I have three Workbooks and all need to be open at once.
The one required at any given time is selected
using "Window" in the Menu Bar.
Each Workbook has an associated and unique Custom Toolbar
brought up when the Workbook is first opened,
using "Auto_Open".
To close each WB there is a button on its associated
toolbar which operates a WB close module (macro).
There are two things I cannot fathom how to do.

1. When I select a different WB (ie one of the other
two via "Window") I need its associated unique toolbar to
be displayed and that of the parting WB removed.

2. When I close a given WB, using its unique
toolbar's close button, I need that toolbar to be removed
and replaced by the one associated with the (next) WB now
appearing.

I can achieve 1 above by putting suitable code in
ThisWorkbook, Workbook Activate.
However when I do 2 above I get an error message
"Application-defined or object-defined error"
I can't find a suitable event kicked off by the closure of
the "old" WB and the arrival of the "new"

Any help or suggestions would be greatly appreciated.
Don