I haven't seen this one for a while and thought it might have been fixed. But here it is again. The command buttons for "UPGRADE" and "SURVEY" sometimes merge so you can't tell a surveyor to survey. It always clears up on the next turn. Here's a screenie. The command buttons are on the lower left corner.
<EDIT> Just for grins, I saved the game, exited and reloaded to see if it would fix it and it did. I don't know if that helps or not. </EDIT>
