I don't know if it can be called a bug, but it's annoying; I'm using Kdenlive 0.7.6 on Ubuntu Jaunty, with N-Vidia GeForce 8400GS and N-Vidia driver 180.44. When editing a project, I have some problems with screen redraw: for example, if I select a clip in the timeline, the name of that clip does not change color to reflect that it's selected, but it does when I hover the cursor over the name. In the same way, when selecting a clip in the timeline that has effects applied, the effect stack does not shows the effect or its parameters until the cursor pass over the screen section where they are.
I've googled for similar problems and I've found nothing, except maybe some questions about screen redraw on KDE, and with other apps, but not with Kdenlive. KDE here is 4.2.2, and I've not seen anything wrong with K3B or Amarok.
On a more positive note, Kdenlive has become to me from 0.7.5 onwards a "must have" application, it's much more stable (I used to save the project every two changes, additions to the timeline, clips added, etc..) and it has all the basic options in a good video editor and more. Congrats and keep up the good job.
And finally, excuse my english!!