isolines displayed within a shape.</li>
<li>\subpage deflection_page "Deflection" - allows to change the
deflection coefficient of a shape.</li>
+<li>\subpage material_page "Material" - allows to change the
+material properties of a shape.</li>
<li>\subpage point_marker_page "Point Marker" - allows to change the
representation of geometrical vertices.</li>
<li><b>Auto color</b> / <b>Disable auto color</b> - activates the auto color
\image html ob_popup_menu.png <br>
<ul>
-<li>\subpage work_with_groups_page "Create Group" - allows creating groups of geometrical objects.</li>
+<li>\ref work_with_groups_page "Create Group" - allows creating groups of geometrical objects.</li>
<li><b>Hide Children</b> / <b>Show Children</b> - hides / shows child
sub-objects in the Object Browser, if the selected geometric object has
child objects. When some child objects are hidden, the name of the
