Kdenlive 0.7.4, Real time playback when moving cutmarks?

Hi there,

after solving the problem with the audio output, i am just facing another problem: At the moment i´m not able to see realtime playback when moving the cutmarks (edges) of my clips as i did in V0.5.
I´m not sure about if it´s some option i just have to check or if it´s a problem with the graphic acceleration or output. The interesting thing is, that the small preview images on the timeline are moving, not very fast, but they do. In the project monitor, i am just getting a still image showing the frame at the position of the marker, not the moving clip edge.

Anyone´s got an idea?