Fix #3138. Remove manual copy class and be more intelligent about what classe can be reassigned.

src/blenderbim/blenderbim/bim/module/root/data.py

@@ -44,6 +44,7 @@ class IfcClassData:
         cls.data["name"] = cls.name()
         cls.data["ifc_class"] = cls.ifc_class()
         cls.data["ifc_predefined_types"] = cls.ifc_predefined_types()
+        cls.data["can_reassign_class"] = cls.can_reassign_class()
 
     @classmethod
     def ifc_products(cls):
@@ -172,3 +173,13 @@ class IfcClassData:
         element = tool.Ifc.get_entity(bpy.context.active_object)
         if element:
             return element.is_a()
+
+    @classmethod
+    def can_reassign_class(cls):
+        element = tool.Ifc.get_entity(bpy.context.active_object)
+        if element:
+            if element.is_a("IfcOpeningElement") or element.is_a("IfcOpeningStandardCase"):
+                return False
+            for product in cls.ifc_products():
+                if element.is_a(product[0]):
+                    return True

src/blenderbim/blenderbim/bim/module/root/ui.py

@@ -62,9 +62,8 @@ class BIM_PT_class(Panel):
                 row.label(text=IfcClassData.data["name"])
                 op = row.operator("bim.select_ifc_class", text="", icon="RESTRICT_SELECT_OFF")
                 op.ifc_class = IfcClassData.data["ifc_class"]
-                row.operator("bim.copy_class", icon="DUPLICATE", text="")
                 row.operator("bim.unlink_object", icon="UNLINKED", text="")
-                if IfcStore.get_file().by_id(props.ifc_definition_id).is_a("IfcRoot"):
+                if IfcClassData.data["can_reassign_class"]:
                     row.operator("bim.enable_reassign_class", icon="GREASEPENCIL", text="")
         else:
             ifc_predefined_types = root_prop.get_ifc_predefined_types(context.scene.BIMRootProperties, context)