From SourceForce comments:

Sadly, this is one of the few subtitle viewers I can find on the PC, none of them are much good. This one does OK, but the seek forwards and backwards buttons don't work. So in order to line your subtitles up you rely on the scroll bar - which isn't very accurate on long video clips such as films, so you have to go forward of the time the film is at, pause it, then press play on your film and wait for it to catch up. Minor time corrections can only be made by pausing one or the other. Also the buttons have some weird auto-hide feature, which is a nice idea, but it works really weirdly so you it's difficult to find the button you want. I went back to version 1.01 because they are less weird and unreliable than the latest which seems to be 1.1.0.

Confirmed.