So today Hammer has been acting up on me and I decided it's best to get online to find some answers. Not sure what went wrong but I was working on my first TF 2 map last night and everything was working fine. But today I can't do anything. The map loads alright, but I can't select any brushes or add in props. Every time I click in the scene the mouse pointer tends to "skip" from where I am clicking to a new spot without selecting anything. Does anyone know what is going on here or has experienced this before? Thanks in advance for helping a new TF2 mapper.