Documentation work

Fixes #920.
Related to #1322.

docs/monitor.dox

@@ -174,6 +174,18 @@ glfwGetMonitorPos(monitor, &xpos, &ypos);
 @endcode
 
 
+@subsection monitor_workarea Work area
+
+The area of a monitor not occupied by global task bars or menu bars is the work
+area.  This is specified in [screen coordinates](@ref coordinate_systems) and
+can be retrieved with @ref glfwGetMonitorWorkarea.
+
+@code
+int xpos, ypos, width, height;
+glfwGetMonitorWorkarea(monitor, &xpos, &ypos, &width, &height);
+@endcode
+
+
 @subsection monitor_name Human-readable name
 
 The human-readable, UTF-8 encoded name of a monitor is returned by @ref