|keycodes|: >
      code           mouse button              normal action
  ---------------------------------------------------------------------------
  <LeftMouse>     left pressed               set cursor position
  <LeftDrag>      left moved while pressed   extend selection
  <LeftRelease>   left released              set selection end
  <MiddleMouse>   middle pressed             paste text at cursor position
  <MiddleDrag>    middle moved while pressed -
  <MiddleRelease> middle released            -
  <RightMouse>    right pressed              extend selection
  <RightDrag>     right moved while pressed  extend selection
  <RightRelease>  right released             set selection end
  <X1Mouse>       X1 button pressed          -
  <X1Drag>        X1 moved while pressed     -
  <X1Release>     X1 button release          -
  <X2Mouse>       X2 button pressed          -
  <X2Drag>        X2 moved while pressed     -
  <X2Release>     X2 button release          -

The X1 and X2 buttons refer to the extra buttons found on some mice (e.g. the
right thumb).

Examples: >vim
        :noremap <MiddleMouse> <LeftMouse><MiddleMouse>
Paste at the position of the middle mouse button click (otherwise the paste
would be done at the cursor position). >vim

        :noremap <LeftRelease> <LeftRelease>y
Immediately yank the selection, when using Visual mode.

Note the use of ":noremap" instead of "map" to avoid a recursive mapping.
>vim
        :map <X1Mouse> <C-O>
        :map <X2Mouse> <C-I>
Map the X1 and X2 buttons to go forwards and backwards in the jump list, see
|CTRL-O| and |CTRL-I|.

                                                *mouse-swap-buttons*
To swap the meaning of the left and right mouse buttons: >vim
        :noremap        <LeftMouse>     <RightMouse>
        :noremap        <LeftDrag>      <RightDrag>
        :noremap        <LeftRelease>   <RightRelease>
        :noremap        <RightMouse>    <LeftMouse>
        :noremap        <RightDrag>     <LeftDrag>
        :noremap        <RightRelease>  <LeftRelease>
        :noremap        g<LeftMouse>    <C-RightMouse>
        :noremap        g<RightMouse>   <C-LeftMouse>
        :noremap!       <LeftMouse>     <RightMouse>
        :noremap!       <LeftDrag>      <RightDrag>
        :noremap!       <LeftRelease>   <RightRelease>
        :noremap!       <RightMouse>    <LeftMouse>
        :noremap!       <RightDrag>     <LeftDrag>
        :noremap!       <RightRelease>  <LeftRelease>
<

==============================================================================
Scrollbars                                              *gui-scrollbars*

There are vertical scrollbars and a horizontal scrollbar.  You may
configure which ones appear with the 'guioptions' option.

The interface looks like this (with `:set guioptions=mlrb`):
>
                       +------------------------------+ `
                       | File  Edit              Help | <- Menu bar (m) `
                       +-+--------------------------+-+ `
                       |^|                          |^| `
                       |#| Text area.               |#| `
                       | |                          | | `
                       |v|__________________________|v| `
 Normal status line -> |-+ File.c              5,2  +-| `
 between Vim windows   |^|""""""""""""""""""""""""""|^| `
                       | |                          | | `
                       | | Another file buffer.     | | `
                       | |                          | | `
                       |#|                          |#| `
 Left scrollbar (l) -> |#|                          |#| <- Right `
                       |#|                          |#|    scrollbar (r) `
                       | |                          | | `
                       |v|                          |v| `
                       +-+--------------------------+-+ `
                       | |< ####                   >| | <- Bottom `