Small Bug in Kdenlive 19.12 RC

[lv at loicvanderstichelen.com]

Hello,

There is a small bug in the RC (and it was not on pervious version).

It happens when you play something on the monitor (from clip or on 
timeline) :

- display something on monitor (clip or timeline)
- play it (play button or spacebar) and stop it
- when you want to go back to previous frame (with left arrow of the 
keyboard), it doesn't work.
- if you go to next frame (right arrow), then it's OK and you can go 
back to previous frame

Loïc