Can't activate a segment - they slip upwards

Maybe I am doing something very silly, but (using the new subtitling plugin) I can't select a segment anymore.

Here's what happened so far:

1) Installed plugins according to wiki.

2) Imported srt file.

3) Opened srt file for translation.

As I click in to a segment to activate it, it does activate, but then Studio activates the next segment above, then the next one etc. until we arrive at segment #84, 55, 39, 8 or 1. This is new behavior. I translated this file with Studio before (the availability of the plugin) and it behaved normally.

There is no way to select a segment using the Editor view (unless I content myself with editing segment 84, 55, 39, 8 or 1).

I can select a segment using the preview window. In about 75% of all cases, the active segment will jump up one (I select segment x and after a split-second of staying on segment x, segment x-1 will become active), but that's it. So I can select a segment and then enter a translation in the editor window.

[EDIT: As I drag the tab of the preview window, the segment that is displayed is activated both in the preview list of segments as well as in the editor. I can't type into the editor right away, most likely because the preview window has the focus, but I can click into the active segment in the editor window and it will stay selected.]

That of course is not really workable and I wonder whether I am doing something wrong? Does anybody else experience this?