When switching to the PartDesign workbench, activate the Body feature that was active when the document was last saved,

and move the selection to its Tip feature so that the user can start creating new features right away

src/Mod/Assembly/App/AppAssemblyPy.cpp

@@ -55,6 +55,7 @@ static PyObject * setActivePart(PyObject *self, PyObject *args)
                 break;
             }
                 
+        ActivePartObject->IsActive.setValue(false);
         ActivePartObject = 0;
         ActiveGuiDoc    =0;
         ActiveAppDoc    =0;
@@ -67,6 +68,7 @@ static PyObject * setActivePart(PyObject *self, PyObject *args)
         // Should be set!
         assert(Item);    
 
+        Item->IsActive.setValue(true);
         ActivePartObject = Item;
         ActiveAppDoc = Item->getDocument();
         ActiveGuiDoc = Gui::Application::Instance->getDocument(ActiveAppDoc);