It's all too complicated for me. So now "too much output" is displayed even if cyclic buffer is not overflown, and no folding is performed for that text. And might never be performed even if it was the last huge stacktrace of a process which might benefit from some folding.

Links are rehighlighted when myLastAddedTextLength is finally "not too much" (maybe extract a method to avoid magic constant duplication?), but this might never be true if a process finishes printing the last huge stacktrace.