Ensure viewprovider is shown after drop from claimChildren3D fixes #0003078

src/Gui/Document.cpp

@@ -1473,6 +1473,7 @@ PyObject* Document::getPyObject(void)
 void Document::handleChildren3D(ViewProvider* viewProvider)
 {
     // check for children
+    bool rebuild = false;
     if (viewProvider && viewProvider->getChildRoot()) {
         std::vector<App::DocumentObject*> children = viewProvider->claimChildren3D();
         SoGroup* childGroup =  viewProvider->getChildRoot();
@@ -1480,6 +1481,7 @@ void Document::handleChildren3D(ViewProvider* viewProvider)
         // size not the same -> build up the list new
         if (childGroup->getNumChildren() != static_cast<int>(children.size())) {
 
+            rebuild = true;
             childGroup->removeAllChildren();
 
             for (std::vector<App::DocumentObject*>::iterator it=children.begin();it!=children.end();++it) {
@@ -1522,4 +1524,28 @@ void Document::handleChildren3D(ViewProvider* viewProvider)
             }
         }
     }
+    
+    //find all unclaimed viewproviders and add them back to the document (this happens if a 
+    //viewprovider has been claimed before, but the object droped it. 
+    if(rebuild) {
+        auto vpmap = d->_ViewProviderMap;
+        for( auto& pair  : d->_ViewProviderMap ) {
+            auto claimed = pair.second->claimChildren3D();
+            for(auto obj : claimed) {
+                auto it = vpmap.find(obj);
+                if(it != vpmap.end())
+                    vpmap.erase(it);
+            }
+        }
+        for(auto& pair : vpmap) {
+            
+            // cycling to all views of the document to add the viewprovider to the viewer itself
+            for (std::list<Gui::BaseView*>::iterator vIt = d->baseViews.begin();vIt != d->baseViews.end();++vIt) {
+                View3DInventor *activeView = dynamic_cast<View3DInventor *>(*vIt);
+                if (activeView && !activeView->getViewer()->hasViewProvider(pair.second)) {
+                    activeView->getViewer()->addViewProvider(pair.second);
+                }
+            }   
+        }   
+    }
 }

src/Gui/ViewProviderGeoFeatureGroupExtension.cpp

@@ -33,7 +33,6 @@
 #include "Application.h"
 #include "Document.h"
 #include <App/GeoFeatureGroupExtension.h>
-#include <Base/Console.h>
 #include <Inventor/nodes/SoGroup.h>
 
 using namespace Gui;
@@ -76,13 +75,10 @@ std::vector<App::DocumentObject*> ViewProviderGeoFeatureGroupExtension::extensio
         //object in the tree
         std::vector<App::DocumentObject*> claim;
         auto objs = ext->Group.getValues();
-        Base::Console().Message("Claim children GeoFatureGroup:\n");
         
         for(auto obj : objs) {            
-            if(obj->getInList().size()<=1) {
-                Base::Console().Message("%s\n", obj->getNameInDocument());
+            if(obj->getInList().size()<=1)
                 claim.push_back(obj);
-            }
         }
         return claim;
     }

src/Gui/ViewProviderGroupExtension.cpp

@@ -110,11 +110,7 @@ void ViewProviderGroupExtension::extensionDropObject(App::DocumentObject* obj) {
 
 std::vector< App::DocumentObject* > ViewProviderGroupExtension::extensionClaimChildren(void) const {
 
-    auto* group = getExtendedViewProvider()->getObject()->getExtensionByType<App::GroupExtension>();
-    Base::Console().Message("Claim children group:\n");
-    for(auto obj : group->Group.getValues())
-        Base::Console().Message("%s\n", obj->getNameInDocument());
-    
+    auto* group = getExtendedViewProvider()->getObject()->getExtensionByType<App::GroupExtension>();    
     return std::vector<App::DocumentObject*>(group->Group.getValues());
 }