- mouse-button-callbackparameter
Called when a mouse button is pressed or released. Expects a function with the signature (lambda (WINDOW BUTTON ACTION MODS) ...). WINDOW is the window where the button was pressed, BUTTON is the name of the mouse button (one of +mouse-button-1+ through +mouse-button-8+, +mouse-button-last+, +mouse-button-left+, +mouse-button-right+, +mouse-button-middle+), ACTION is one of +press+ or +release+, and MODS is a bit field describing the modifier keys that were held down (any of +mod-shift+, +mod-control+, +mod-alt+, or +mod-super+).