| x | The x-coordinate (in client coordinates) where the mouse button was pressed. |
| y | The y-coordinate (in client coordinates) where the mouse button was pressed. |
| button | The mouse button that was pressed. It will be one of the following values. mbLeft : The left mouse button was pressed mbMiddle : The middle mouse button was pressed mbRight : The right mouse button was pressed mbX1 : The first side mouse button was pressed mbX2 : The second side mouse button was pressed |
| shift | The state of the modifier keys pressed at the same time as the mouse button.
This is a bitwise OR combination of the following values. ssAlt : The ALT key was pressed ssShift : The SHIFT key was pressed ssCtrl : The CTRL key was pressed |