Minor fix for Link lookups
@@ -1223,7 +1223,8 @@ class LinkCallback(param.Parameterized):
return (plot, links)
else:
if ((link.target is source) or
- (link.target._plot_id is not None and
+ (link.target is not None and
+ link.target._plot_id is not None and
link.target._plot_id == source._plot_id)):
return (plot, [link])
