I understand that there is a limit of 200 unique values when symbolizing in Portal. On that note, when you ungroup the remaining values to reach this limit, it no longer lists the remaining values. (See image 1 & 2)
It would be great if, even though it won't ungroup more than 200 colored values, you can at least see the full list of greyed out values. That way, you can then go in and drag values from the colored symbols to the grey and moved the grey ones to the colored ones.
This way you would still see the maximum number of unique colored values on the map but you can make sure the important values that you want to be colored are shown too.