definite filter to selection of triangles.</li>
<li><b>Apply to all</b> radio button allows to modify connectivity and
type of all triangles of the currently displayed mesh or sub-mesh.</li>
+<li><b>Preview</b> provides a preview in the viewer.</li>
<li>\b Criterion menu allows to choose a quality criterion,
which will be optimized to select triangles to unite.</li>
<li><b>Select from</b> set of fields allows to choose a sub-mesh or an
