Open the Colonies List window (the one that sits on top of the main map on the left side of the screen). Make sure that the list contains enough colonies such that some of them are not visible unless you scroll down. Click on the ship production for the first colony listed at the top. When the ships list pops up to the right, choose a different ship to build and then click Done (or whatever the button is labeled to accept the change). The Colonies List will scroll away from the colony that you just modified for no apparent reason.
This is very irritating when you have a lot of colonies. I use this list to manage ship production frequently because I can see the list and the map at the same time (unlike the colony mgmt screen). Please fix.