Gui: add 'Select group contents' context menu item (#22082)

* Gui: add 'Select group contents' context menu item

* Gui: remove dependency from Draft icon

src/Gui/ViewProviderDocumentObjectGroup.cpp

@@ -23,6 +23,12 @@
 #include "PreCompiled.h"
 
 #include <App/DocumentObjectGroup.h>
+#include <App/Document.h>
+#include <Gui/Selection/Selection.h>
+#include <Gui/BitmapFactory.h>
+#include <QMenu>
+#include <QAction>
+#include <QObject>
 
 #include "ViewProviderDocumentObjectGroup.h"
 #include "Application.h"
@@ -82,6 +88,51 @@ void ViewProviderDocumentObjectGroup::getViewProviders(std::vector<ViewProviderD
     }
 }
 
+void ViewProviderDocumentObjectGroup::setupContextMenu(QMenu* menu, QObject* receiver, const char* member)
+{
+    // First, call the base class implementation to get all the standard menu items.
+    ViewProviderDocumentObject::setupContextMenu(menu, receiver, member);
+
+    App::DocumentObject* obj = this->getObject();
+
+    // This action is only for plain "Std::Group" objects, not for derived types like "Draft::Layer".
+    // We check the TypeId to ensure we don't add this menu to other group-like objects.
+    if (obj->getTypeId() == App::DocumentObjectGroup::getClassTypeId()) {
+        auto* group = static_cast<App::DocumentObjectGroup*>(obj);
+
+        // Only add the action if the group actually contains objects.
+        if (group && !group->getObjects().empty()) {
+            // Add the custom action.
+            QIcon icon = BitmapFactory().iconFromTheme("Std_SelectGroupContents");
+            QAction* selectAction = new QAction(icon, QObject::tr("Select group contents"), menu);
+            selectAction->setToolTip(QObject::tr("Selects all objects that are children of this group."));
+
+            // Connect the action's triggered signal to a lambda function that performs the selection.
+            QObject::connect(selectAction, &QAction::triggered, [group]() {
+                if (!group) return;
+
+                // Use getAllChildren() to recursively select contents of subgroups.
+                const auto& children = group->getAllChildren();
+
+                if (!children.empty()) {
+                    const char* docName = group->getDocument()->getName();
+
+                    Gui::Selection().clearSelection(docName);
+
+                    // Add each child object to the selection individually.
+                    for (App::DocumentObject* child : children) {
+                        if (child && child->isAttachedToDocument()) {
+                            Gui::Selection().addSelection(docName, child->getNameInDocument());
+                        }
+                    }
+                }
+            });
+
+            // Insert the action at the top of the menu for better visibility.
+            menu->insertAction(menu->actions().isEmpty() ? nullptr : menu->actions().first(), selectAction);
+        }
+    }
+}
 
 // Python feature -----------------------------------------------------------------------