Interface for mouse events.
| actionKey | Returns true if the platform-specific action key is pressed. This key is Cmd on macOS, and Ctrl on all other platforms. |
| altKey | Return true if the Alt key is pressed. |
| button | Integer that indicates which mouse button is pressed: 0 is the left button, 1 is the right button, 2 is the middle button. |
| clickCount | The number of times the button is pressed. |
| commandKey | Return true if the Windows/Command key is pressed. |
| ctrlKey | Return true if the Ctrl key is pressed. |
| localMousePosition | The mouse position in the current target coordinate system. |
| modifiers | Flag set holding the pressed modifier keys (Alt, Ctrl, Shift, Windows/Command). |
| mouseDelta | Mouse position difference between the last mouse event and this one. |
| mousePosition | The mouse position in the panel coordinate system. |
| pressedButtons | A bitmask that describes the currently pressed buttons. |
| shiftKey | Return true if the Shift key is pressed. |