Add opening symbols to clones of windows

The method execute must create the sshapes and vshapes objects. They must
1. exist in the cloned (parent) object (by calling the execute function)
2. and be copied to the clone object.
Then the SVG rendering in ArchSectionPlan can find it.

src/Mod/Arch/ArchWindow.py

@@ -697,6 +697,13 @@ class _Window(ArchComponent.Component):
     def execute(self,obj):
         
         if self.clone(obj):
+            clonedProxy = obj.CloneOf.Proxy
+            if not (hasattr(clonedProxy, "sshapes") and hasattr(clonedProxy, "vshapes")):
+                clonedProxy.execute(obj.CloneOf)
+            self.sshapes = clonedProxy.sshapes
+            self.vshapes = clonedProxy.vshapes
+            if hasattr(clonedProxy, "boxes"):
+                self.boxes = clonedProxy.boxes
             return
         
         import Part,DraftGeomUtils,math