Hi, I have been working on a drawing but today when I opened my CS6 and wanted to erase a few things it doesn't let me. (Nothing pops up and nothing happens) The weird thing is I can draw on the layer and erase new lines but I can't erase the lines I made of yesterday which is quite annoying. I'm on the active layer and my brush opacity is on 100%.

Does anyone know what's going on and how to fix it?

[edit] I solved the problem myself. It was the history eraser which I had to turn off and now works everything as it should.