Notification to the user that a body is not active when inserting a datum entity - fixes #2511

src/Mod/PartDesign/Gui/Command.cpp

@@ -133,6 +133,8 @@ void UnifiedDatumCommand(Gui::Command &cmd, Base::Type type, std::string name)
             }
             cmd.doCommand(Gui::Command::Doc,"App.activeDocument().recompute()");  // recompute the feature based on its references
             cmd.doCommand(Gui::Command::Gui,"Gui.activeDocument().setEdit('%s')",FeatName.c_str());
+        } else {
+            QMessageBox::warning(Gui::getMainWindow(),QObject::tr("Error"), QObject::tr("There is no active body. Please make a body active before inserting a datum entity."));
         }
     } catch (Base::Exception &e) {
         QMessageBox::warning(Gui::getMainWindow(),QObject::tr("Error"),QString::fromLatin1(e.what()));