I recently bought SE on Steam and while watching a DasTactic video on how to play I noticed he had tooltips for each planet he hovered his mouse pointer over. In my game I have no tooltips when I hover over a planet. Tooltips work fine elsewhere in the UI.
As I understand it, the Launcher and main menu are actually a different programm from the main game.
The main game starts at planet selection process. It has a different and much expanded set of options. There was at least one setting regarading tooltips. Try properly starting a game and then look in the options.