Reset or reinitialize a tooltip?

[uladz]

Guys, is there a way to reset and force reinitialization of a tooltip control? Basically what I'm trying to do is to add different info to an item tooltip depending on which keys are pressed and I want to do it on-the-fly, i.e. when I mouse over an item in my inventory and get a tooltip then when I press Shift then I get some extra info added to this tooltip, when I release Shift the extra info has to go away. So far I was able only to add extra info to tooltip on Shift but I can not remove it. Was looking for functions that would allows me to force reset of this tooltip but could not find anything working. Any hints or ideas would be much appreciated.