Fixes for Layout/Overlay path resolution

holoviews/core/layout.py

@@ -338,14 +338,14 @@ def new_path(cls, path, item, paths, counts):
             path = path[:2]
             pl = len(path)
             count = counts[path[:-1]]
+            counts[path[:-1]] += 1
             if (pl == 1 and not item.label) or (pl == 2 and item.label):
                 new_path = path + (int_to_roman(count-1),)
                 if path in paths:
                     paths[paths.index(path)] = new_path
                 path = path + (int_to_roman(count),)
             else:
                 path = path[:-1] + (int_to_roman(count),)
-            counts[path[:-1]] += 1
         return path
 
 
@@ -374,10 +374,10 @@ def _unpack_paths(cls, objs, paths, items, counts):
         Recursively unpacks lists and Layout-like objects, accumulating
         into the supplied list of items.
         """
-        if isinstance(objs, cls):
+        if type(objs) is cls:
             objs = objs.values()
         for v in objs:
-            if isinstance(v, cls):
+            if type(v) is cls:
                 cls._unpack_paths(v, paths, items, counts)
                 continue
             group = group_sanitizer(v.group)