A few weeks ago I mentioned a work around for the Quick Click category bug, where the category is not saved when Outlook 2007 closes.
There is a bug in Outlook 2007 where it forgets the quick click category at startup.
It (and a long list of other bugs) is fixed in a new hotfix:
Description of the Office Outlook 2007 hotfix package (Outlook-x-none.msp): October 27, 2009
I recommend reviewing the KB article for all the issues that are fixed by this hotfix as it addresses a lot of problems, including issues opening *.msg attachments, several calendar issues, dismissed reminders returning and more. Lots more.
Published October 30, 2009. Last updated on January 9, 2012.