Preferences window (Left Button)
The Preferences window is where you adjust the global settings for the program and all fractal windows. The Left Button page contains the settings to control how the left (primary) mouse button works in the program.
To open the Preferences window's Left Button page: On the File menu, click Preferences, then click the Left Button tab.
The other tabs are for miscellaneous settings and the right button.
The default settings let you scroll, scale (zoom), rotate, set the julia seed, show the fractal calculation path, zoom-in by two, and zoom-in by four.