Cropping Video Clip Duration not working!

When I crop a video clips duration, whether by using the razor tool or editing it manually by right clicking the video clip in the timeline and selecting edit duration, the project monitor and the rendered file displays the the video clip from it's 00:00:00:00 point rather than the point that I chose. Usually even the 'crop end' parameter changes automatically to a value less than the 'crop start' parameter's value.

This error occurs when I save and reload my project. Even though the video's duration is supposedly cropped it plays from it's 00:00:00:00 point anyway.

Info: I'm using the 0.7.8 version of kdenlive and the video clips I using is of .mkv format.