Assembly: Fix context menu 'Activate object' not working and causing crash (#17092)

* Assembly: Add setupContextMenu to ViewProviderAssembly.h

* Assembly: Fix right click 'activate object' menu not setting edit

* add QMenu header

* Add NOLINT

* Add one more space before //NOLINT or clang cries...

* Fix isInEditMode

* add isInEditMode to ViewProviderAssemblyPy.xml

* add isInEditMode to ViewProviderAssemblyPyImp.cpp

* update activeAssembly() in Utils to make sure isInEditMode

src/Mod/Assembly/Gui/ViewProviderAssembly.cpp

@@ -27,6 +27,7 @@
 #include <boost/core/ignore_unused.hpp>
 #include <QMessageBox>
 #include <QTimer>
+#include <QMenu>
 #include <vector>
 #include <sstream>
 #include <iostream>
@@ -48,6 +49,7 @@
 
 #include <Base/Tools.h>
 
+#include <Gui/ActionFunction.h>
 #include <Gui/Application.h>
 #include <Gui/BitmapFactory.h>
 #include <Gui/CommandT.h>
@@ -112,6 +114,20 @@ QIcon ViewProviderAssembly::getIcon() const
     return Gui::BitmapFactory().pixmap("Geoassembly.svg");
 }
 
+void ViewProviderAssembly::setupContextMenu(QMenu* menu, QObject* receiver, const char* member)
+{
+    auto func = new Gui::ActionFunction(menu);
+
+    QAction* act = menu->addAction(QObject::tr("Active object"));
+    act->setCheckable(true);
+    act->setChecked(isActivePart());
+    func->trigger(act, [this]() {
+        this->doubleClicked();
+    });
+
+    ViewProviderDragger::setupContextMenu(menu, receiver, member);  // NOLINT
+}
+
 bool ViewProviderAssembly::doubleClicked()
 {
     if (isInEditMode()) {
@@ -292,12 +308,7 @@ void ViewProviderAssembly::setEditViewer(Gui::View3DInventorViewer* viewer, int
 
 bool ViewProviderAssembly::isInEditMode() const
 {
-    App::DocumentObject* activePart = getActivePart();
-    if (!activePart) {
-        return false;
-    }
-
-    return activePart == this->getObject();
+    return asmDragger != nullptr;
 }
 
 App::DocumentObject* ViewProviderAssembly::getActivePart() const