I've noticed this happening with more and more blogs being tagged as having explicit content which forces you to login to tumblr where it stupidly gives you the dashboard screen.
It used to be possible to dismiss the dashboard sidebar to a pull-out tab at the left of the screen but I haven't been able to do this for a few weeks. I don't know whether one of my blockers is affecting it and haven't bothered to find out. I don't waste my time with tumblr these days as there are many more sites that offer so much more.
