[Narinka]

Sigg, dunno why, but your suggested code works not well enough with Latch repaint and I don't like to set up periodic repaint in every window I use.

Just try to do something like simple frame with scripted var + texture + show/hide feature or whatever..

Scripted var with buff event checked:
vBuff = true;
if unit:HasBuff("YourBuffGoesHere") then vBuff = false end

Window with latch repaint.

Now drop your buff, buff it back etc.. it just updates in some weird way.

If you change scripted var to something like:
vBuff = true;
if UnitBuff("player", "YourBuffGoesHere") then vBuff = false end;
Then everything works fine.