[kpreid]

Not a bad idea to respond to visibility, but to solve the blob problem it would be better to explicitly synchronize text creation and text position. This is basic in game/simulation programming: you don't want the rules of the game to change depending on the performance of the computer — it may be slower, but it should be internally consistent.

For example, have a single, explicit 'scroll position' or 'time' variable (they're equivalent in this case), increment it on a timer, and insert new text when (time mod N) rolls over.