It would be very helpful in the colony manager screen if there was some indication of the maximum population on each of the colonies.

I love how the PQ/class indicator shows the number of unused tiles in parentheses. Maybe the population column could do the same -- currentpop (maxpop). This way I don't have to guess whether that planet with 9.0 population needs a farm, or if it just happens to have 9b people on its way to 13b.

If there isn't room in the column for the actual numbers, maybe the population number could be color coded:

Green: the planet has room for more population growth
Yellow: the planet is at max population, build some farms!
Red: the planet is above max population, get some transports here!