Avidemux 2.5.2

[shivz@013.net]

My only purpose is to cut/split/trim self made DVD's, downloaded to the hard disk. No further editing.
I was advised that if the disks were self made/rcorded, and if all I wanted was cutting/splitting'trimming - then, Avidemux could do the job, VOB files notwitstanding.
I downloaded it (Avidemux 2.5.2), it 'read' my files, but then I could not drag the bar. Other functions could not be activated as well.
Where have I erred?

[hech54]

Open the first VOB file in the VIDEO_TS folder.
Index it? YES
Append it? YES
Only cut on key frames (>>) to avoid needing to re-encode

[Bjs]

Dvdshrink in reauthor mode