Some program functions are only accessible via the keyboard:

Make board window square | F9 |
Delete coloured fields/arrows on the board | Ctrl-Alt-Y |
Add an exclamation mark (good move) | ! |
Copy game and position to clipboard | Ctrl-C |
Clear hash tables | Ctrl-Shift-Alt-H |
Change engine parameters | Ctrl-Shift-P |
Delete all game comments | Shift-Ctrl-Y |
Stop running engine | Esc |
Switch between book and notation | Tab |
Go to position after move N | Ctrl-G |
Note: You can view the current assignment of keyboard shortcuts or change them later.