In the upper right corner of the Arrange window are two tool menus, the left-click tool menu selects the default tool that is used most of the time:
The Command-click Tool menu selects the tool that is active when the Command key is held:

When doing a lot of crossfades while editing audio, for example, it can speed up workflow to assign the Crossfade tool in the command-click tool menu:
Then when a crossfade is needed, hold the command key to change the cursor to the Crossfade tool.
A third tool can be assigned to Right-click when using a mouse with Right-click capability.
Choose Logic Pro > Preferences > General, choose the Editing tab, and from the Right Mouse Button pop-up menu select Is Assignable to a Tool:
We now have three tools available with fast access, to speed up workflow. I like to set the three tools in the Arrange window to Pointer (Left-click), Crossfade or Marquee (Command-click), and Zoom (Right-click):

When cutting up a lot of Regions in the Arrange window, try putting the Command-click Tool on Marquee, then hold the Command key, click and drag with the Marquee Tool to make selections:

In the Piano Roll try setting the Command-click Tool to Velocity when editing MIDI notes:

Then hold the command key to bring up the velocity tool:

Right-click mouse functionality can speed things up considerably when using three tools in Logic Pro.
The Right-click can also be assigned to open the Tool Menu.
Choose Logic Pro > Preferences > General, choose the Editing tab, and from the Right Mouse Button pop-up menu select Opens Tool Menu:
The default Key Command to open the Tool menu is the escape key (the key marked esc).




