left-click-drag     : rotate surface
    middle-click-drag   : shift surface
    right-click         : node selection
    right-click-drag    : drag node selection
                          [in drawing mode] draw


    ctrl + left-drag    : pry hemispheres apart (walnut brain)
                          up/down    -> open angularly
                          left/right -> separate
    ctrl + double-left-click : undo 'walnut brain' actions


    alt + l             : rotate to look at crosshair point
    shift + left-drag   : rotate about central axis
    shift + middle-drag : zoom (see also 'z')


    ctrl-h              : help (open searchable help window)
    ctrl-s              : open surface/object controller
    ctrl-n              : open additional viewer
    g                   : open time series graph window


    arrow keys          : make small rotations
    <home>              : reset zoom and translation parameters


    t                   : (toggle) talk to afni
    z/Z                 : zoom
    m                   : (toggle) motion mode on/off
    r                   : record one image (also applies to colorbar)
    R                   : (toggle) continuous recording on/off
    ctrl-r              : record one image directly to disk
    ./,                 : (select) surface state
    <space>             : (toggle) between current and mapping reference state
    p                   : (select) points/lines/triangles
    []                  : (toggle) show hemispheres

    D			: toggle "dot product", e.g. for running InstaCorr