Ribbon displays labels even when showLabel is set to False
 

I am running Office 2007 on Windows XP professional. I created an add-
in to customize the ribbon with several built-in buttons. I set
several buttons as showLabel="false" to only show the button image.

If I open Excel from the Start Menu, my add-in loads correctly for all
the buttons where I have showLabel="false".

When Excel is closed and I try opening a file directly from Windows
Explorer or from an email, the showLabel="false" attribute is ignored
and all of the labels appear that I was trying to hide.

Is there something I should be doing during the initialization to have
the labels properly hidden or is this a bug in the program. Please
help!