Subtitles in iMovie '09 (version 8.0.2)

Hi,

I'm trying to add subtitles to my movie in iMovie '09 and there seems to be a glitch. I select the portion that I want to add the subtitle to, then drag the title type that I want to use to that selected portion. However, instead of just occupying the selected portion, it takes up an entire 3'22" (you can see in the picture below that it says '3:22 marked'). I can then shorten it to the length that I want, but it then won't allow me to put in any other subtitles where the 3'22" occurred.

Can anybody tell me why this is happening and how I can fix it please? I need to add subtitles for an entire wedding ceremony so I need a lot of little segments.