There is next to no necessity at all to use a mouse in any of the LCAU programs, but there are one or two occasions in which there is a movable cursor present. Either the four keyboard arrows, or some of the older equivalents such as space and backspace, can be used to move the cursor.
No mouse drivers are included in LCAU , but there are many ``external'' mice (mouses?) on the market which work by inserting characters into the input buffer of the computer to which they are attached.
Such a mouse can be programmed to create arrows corresponding to its movements, CONTROL ARROWs for the two buttons, and ESCAPE for a double button press. It will then be compatible with the option assignments in LCAU .