+\anchor reversed_edges_helper_anchor
+<h2>Reversed Edges Helper</h2>
+
+\image html rev_edges_helper_dlg.png
+
+\b Helper group assists in defining <b>Reversed Edges</b>
+parameter of the hypotheses depending on edge direction.
+
+<b>Show whole geometry</b> check-box allows seeing the whole
+geometrical model in the 3D Viewer, which can help to understand the
+location of a set of edges within the model.
+
+<b>Propagation chains</b> group allows defining <b>Reversed Edges</b>
+for splitting opposite edges of quadrilateral faces in a logically
+uniform direction. When this group is activated, the list is filled
+with propagation chains found within the shape on which a hypothesis
+is assigned. When a chain is selected in the list its edges are shown
+in the Viewer with arrows, which enables choosing a common direction
+for all chain edges. \b Reverse button inverts the common direction of
+chain edges. \b Add button is active if some edges of a chain have a
+different direction, so you can click \b Add button to add them
+to <b>Reversed Edges</b> list.
+
+\image html propagation_chain.png "The whole geometry and a propagation chain"
+
+\note Alternatively, uniform direction of edges of one propagation
+chain can be achieved by
+\ref constructing_submeshes_page "definition of a sub-mesh" on one
+edge of the chain and assigning a
+\ref propagation_anchor "Propagation" additional hypothesis.
+Orientation of this edge (and hence of all the rest edges of the chain) can be
+controlled by using <b>Reversed Edges</b> field.
+