A general rule of thumb in the RJ is switches that are marked with three dots are three-position switches, and switches that don't have any dots are two-position switches (although this may not always be the case). Therefore, when hovering your mouse over a three-position switch, the mouse cursor will turn to an up/down arrow indicating which direction the switch will move in when clicked. If a 'halt' hand is visible, that means the switch cannot be moved in that direction, either due to the switch not having another position in that direction, or a baulk (red square next to the switch) preventing the switch from moving.
Mark - Just Flight