OK for the Thinkpad r50e with black web pages (e.g., Speed Dial page is black, although mouseover still shows link previews in the corner.):
I notice for user me (who started icewm) and root, I get the problem. But for # su - some_other_user $ midori I DON'T get the problem. Instead I get a different problem, ** (WebKitWebProcess:3333): WARNING **: Couldn't register with accessibility bus: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. libGL error: failed to open drm device: Permission denied libGL error: failed to load driver: i915 and midori works fine. However for the users getting the black screens, in Preferences unchecking [ ]Enable WebGL support and restarting midori doesn't help.