The 'None' mode is the default editor mode when opening the map editor. The size of brushes and sprays can be increased and decreased using Numpad + and Numpad. Placing entities/tiles/decoratives is done using Left mouse button, they can be removed with Right mouse button. All editor modes use Q to clear the cursor, like the normal game. Each of the modes provides different tools and ways to change the map. The 'Tools' tab in the GUI shown in the top left when using the map editor allows to switch between different map editor modes.
