These tools enable to measure geometric properties of molecules in an interactive fashion. Distances (bond lengths or any interatomic distances), bond angles and dihedral angles can be measured. Results are displayed in monitors that are small labels on the canvas linked to the structure. When the structure is rotated these monitors move along, and when the structures are manipulated by control monitors are refreshed automatically to reflect any changes in the geometry of the structures instantly.
Monitors are easy to use: select the type of monitor appropriate for the property to be measured (ie. distance, bond angle, dihedral angle), then select the appropriate number of atoms one by one (single click with left mouse button). When the last atom (ie. second, third or fourth depending on the type of monitor) is selected the monitor appears on the canvas.
Monitors themselves can be selected by single click of left mouse button just like any other component visible on the canvas. When selected, they can be deleted (ie. removed forever), and they can also be hidden (ie. removed from the canvas temporarily). Hidden monitors can be shown again, use the right mouse button pop up menu.