Hi

I am working on a ADD-IN for excel.I have requirement as follows.

1) I have created a Excel command bar and created some command butttons on
it.
2) Button Start is a default command button which gets loaded with other
buttons and shown to the user (Visble=true) and other buttons are hidden
(visible=false).
3) The other buttons gets visible on some condtion i.e if a sheet named
mySettings gets loaded to the workbook then they will appear to the workbook
otherwise they will disapper (hideen).
4) I am searcing a event that will fire and search for the perticaulr sheet
in workbook and gets activate and deactivate the command buttons on the
command bar.

If i am missing something then plz let me know so that i can make it more
presise.

Thanks

__Das