Function:   MouseShow()

               A call to this function will make the mouse Cursor
               Visible, generally the Mouse Cursor will be the
               current character on the complementary (XORed)
               color attribute, but it could also be some other
               character defined by MouseChar(). MouseThere()
               does not make the mouse cursor visible, so
               MouseShow() has explicitly to be called.
               MouseHide() will make the mouse invisible again,
               it is crucial to hilight the fact that Multiple
               calls to MouseShow() require multiple calls of
               MousHide() for it to dissapear, and vice versa.
               Keep this in mind as it is the source of quite
               some confusion, not in the least place has it been
               so for myself.

   Syntax:     MouseShow()

   Arguments:  None.

   Returns:    Nothing.