I have just installed Elementary OS on an old MacBook Pro with an Nvidia graphics card. The driver verson is 340.107. The problem is that the screen is flickering most of the time at the bottom (where you can find the dock). As long as the screen is empty there is no flickering. It starts when I move the mouse or start an app. I have tried to find a solution, but have not been successful yet. What can I do to stop that flickering?