Ctrl+Alt+click : Add a secondary caret
Ctrl+Alt+double-click : Add a secondary word selection
Ctrl+Alt+click+drag : Add a secondary selection
Shift+Alt+. : Add the next matching text as a selection
Shift+Alt+; : Add all matching text as selections
Shift+Alt+, : Remove last selected occurrence
Shift+Alt+/ : Skip next matching occurrence
Alt+click : Add a box selection
Esc or click : Clear all selections