The 2D Views options allow you to configure a number of the editor's behaviors. Settings here will depend largely on personal preference.
Options
Crosshair cursor
- when this is enabled, the cursor will turn into a crosshair when it
is over a brush.
Grid
Size
- This determines the initial grid size when you start a new
map. The options are 8, 16, 32, 64, 128, and 256 units. You can
change the grid size while editing by pressing "[" and "]".