The properties editor allows you set any of the properties of the selected objects using individual controls specific to each of the objects parameters.
The Polyline/Polygon Properties Editor
To see what each of the editor's controls does: move the mouse cursor over the control in DEX (not this help topic) and a popup tooltip will appear.  A Typical Popup Tooltip for a Control Can't See the Tooltips? If you cannot see the tooltip: make sure the Show Tooltips check button on the left of the DEX status bar is 'checked'.  The Show Tooltips Check Button |