On the sheet, the cells of both corners and the offsets into them; an absolute anchor
states tl as a position and br as a size, with no cells. A member of a group is always
the latter, in the group's child space (IGroup.JSON.childBounds).
OptionalanchorThe behavior of how the movable resizes as the anchor/cells change.
OptionalclientThe content of the movable object.
OptionalflipMirrored left to right within the frame.
OptionalflipMirrored top to bottom within the frame.
OptionalhiddenIf true then the movable object is hidden.
OptionallockWhether resizing should keep the aspect ratio.
Optionallockslock specific fields
OptionalrotationThe rotation in degrees.
The anchor for the movable object.