The Colour Categories window starts off like the Find window but adds colour options.
Example
With a word list I started by specifying what I wanted to find, words ending -ED.
After pressing OK I got this window:
When I chose the colour yellow and pressed Add a search, I got this:
Now pressing Find all I got this:
The word list shows the hits with the Set column coloured.
To group the words ending in -ED, I need to choose the Alphabetical view and sort on the Set column.