Tooltips on any objects on the ground would be really helpful.

There is also a blue potion for mana too I thought.

What about tooltips on the empty slots as well. Are they all the same? Some have different backgrounds, and I'm not sure what they do.

The UI needs to be changed so clicking on anything (buildings, towers, items, units) should bring up a portrait (like you get when attacking someone now) that shows information on it like it's health(dmg, armor, mana if they're allies), and for drops it'd say if they're health, aman, whatever isuppose.

BUt yeah, you can jsut try and see on em.  green is health, blue scrolls mana.

It seems to be treating every pixel as its own tooltip active area, because any motion makes it disappear rather than move.