Elevation Filter Updates (#9635)

Backports #9610

docs/user_manual/map_views/map_view.rst

@@ -315,7 +315,10 @@ clicking on the :guilabel:`Data Filtering` in the :guilabel:`View` menu. The
 side of the map canvas. At the top of the slider, there is a |settings| :sup:`Settings` menu
 where you can:
 
-* set the :guilabel:`Fixed range size` to limit elevation range to a fixed size
+* Set the :guilabel:`Fixed Range Size` value to lock the elevation range to a specific size.
+  This setting is saved within the project and retained across sessions, ensuring consistency
+  for your elevation filter. Use the |checkbox| :guilabel:`Invert Direction` option to reverse
+  the elevation filter slider, so that it moves from high values at the bottom to low values at the top.
 * :guilabel:`Set Elevation Range` to open the project elevation tab, where you can set dedicated lower and upper bounds for the elevation range
 * :guilabel:`Disable Elevation Filter` to remove the elevation filter from the map canvas