<ul>
<li><b>Id Elements</b> field allows to specify the elements which
-should be smoothed by selecting them in the 3D viewer (lock \b Shift
-button to select several elements).</li>
-<li><b>Select whole mesh, submesh or group</b> - smoothing is applied
-to the whole mesh or its part.</li>
-<li><b>Fixed nodes ids:</b> some nodes keep their location during
+should be smoothed
+<ul>
+<li>Check on <b>Select the whole mesh, submesh or group</b> option
+<li>Choosing them manually with the mouse in the 3D Viewer. You can
+click on an element in the 3D viewer and it will be highlighted</li>
+<li>Applying Filters. The <b>Set filter</b> button allows to apply a
+definite filter to selection of the elements. See more
+about filters on the
+\ref selection_filter_library_page "Selection filter library" page.</li>
+</ul>
+</li>
+<b>Fixed nodes ids:</b> some nodes keep their location during
smoothing. If a mesh is built on a geometry shape, the nodes built on
geometrical edges are always fixed. If smoothing is applied to a part
of a mesh then the boundary nodes of an elements set are also
-fixed. Any other nodes may be additionally fixed.</li>
+fixed. Any other nodes may be additionally fixed. Fixed nodes can be
+selected manually or by filters too.</li>
<li><b>Smoothing Method:</b>
<ul>
<li>\b Laplacian smoothing pulls a node toward the center of
