With the icon list coming on the right for ship completed or planet with nothing to build, I find myself cycling to quickly through the planets with nothing to build. Often I find that I closed one before I meant too. With large empires looking that planet up will be difficult as I usually don't remember the name. For this I would suggest adding a button to reopen the colony management screen of the lastly opened colony.

The hard part would be finding a nice place for the button in the interface, anyways it's just a suggestion, thanks for reading it!

G-Force