PLT plot. Add None to wells drop down if no wells are loaded

ApplicationCode/ProjectDataModel/Flow/RimWellPltPlot.cpp

@@ -1413,6 +1413,11 @@ void RimWellPltPlot::calculateValueOptionsForWells(QList<caf::PdmOptionItemInfo>
             options.push_back(caf::PdmOptionItemInfo(wellName, wellName));
         }
     }
+
+    if (options.size() == 0)
+    {
+        options.push_back(caf::PdmOptionItemInfo("None", "None"));
+    }
 }
 
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