Fix projection data domain duplicate checking.

Author: NejcDebevec

Orange/widgets/visualize/utils/widget.py

@@ -710,9 +710,11 @@ def _get_projection_data(self):
         proposed = [a.name for a in self.projection.domain.attributes]
         names = get_unique_names(self.data.domain, proposed)
 
-        attributes = tuple([a.copy(name=n) for n, a in
-                            zip(names, self.projection.domain.attributes)]) \
-            if proposed != names else ()
+        if proposed != names:
+            attributes = tuple([attr.copy(name=name) for name, attr in
+                                zip(names, self.projection.domain.attributes)])
+        else:
+            attributes = self.projection.domain.attributes
         return self.data.transform(
             Domain(self.data.domain.attributes,
                    self.data.domain.class_vars,