Strange lines on clips

Hi,

I 've just bought Nuendo 6.5 second hand, and in the clips there are appearing strange dotted lines (look in the photo). When I used version 7 trial for 3 months there wasn’t any thing like that.
Anyone knows how to turn it off if its possible? It make a troubles, because I cannot see properely the waveform when audio is silent…

Best,
Jarek

Turn off Automatic Hitpoint detection.

Fredo