Dividend categories
When entering dividends for a particular investment in Microsoft Money, either using the "dividend" or "reinvest dividend" activities, it is not possible to enter a category into Microsoft Money. This can be seen in the image below.

Microsoft Money does actually assign a category to the transaction though. Usually it is Investment Income:Dividends, although the name can be changed.
To use a different category, go to the options setting at tools->settings->investment categories. The setting for dividends will be noted in the displayed window (see image below)

If you want to change the category from the default (investment income:dividends) then you can do so here.
Viewing this category through the categories place in Microsoft Money will list previously entered dividends.
Keywords: dividend, category, investment