Required versus ability tooltip

- I think there should be a tooltip (mouse-over) that tells you how close you are to a requirement. For example, curved stairs require building level 6. A mouse-over tooltip that says "your highest level of building is 4" would help. Then I can see how close I am, and whether it would be worthwhile to have the noble buckle down on all building to level up as fast as possible (because I'm "right there" in level), or just let the game play out for a bit and then recheck (because OMG, that is a 12-hour grind).