Tab to or mouseclick on the diagram and use the following keys for interactive exploration:

AActivate keyboard driven exploration
BActivate menu driven exploration
EscapeLeave exploration mode
Cursor downExplore next lower level
Cursor upExplore next upper level
Cursor rightExplore next element on level
Cursor leftExplore previous element on level
Alternative keymap uses E/D/S/F for directions.
XToggle description mode
MDe/activate direct magnification
NDe/activate stepwise magnification
SToggle subtitles
CCycle contrast settings
TMonochrome colours
LToggle language (if available)