Keyboard freeze when using hyperlinked sheets
 

I experience some strange Excel behaviour:

I am opening a workbook using a hyperlink form another workbook.
The called workbook then runs a macro (OnWorkBookOpen event), does
something, and then closes itself without saving changes.
The calling workbook does not do anything (it just receives some data from
the opened workbook).

Although the macro has done its job (data transferred, called workbook
closed) I get the following annoying behaviour:
- the status bar and timer seem to say that Excel is busy calculating...
- I get some warning about the called workbook trying to open again asking
me if I want to run it although it contains macros (although my macro
security is set to "low"). If I answer "Cancel" to the dialog, everything
goes fine, but if I click "OK" my keyboard freezes for anything I do in
Excel (not other programs.

Weird! Does anybody have an explanation to this type of behaviour?

The reason why I have used this setup is because I want the macro to reside
in the one called file (it can be called from 110 different files at random
by users).

Thanks for any help!

Robin