catched it

saqc/lib/plotting.py

@@ -235,7 +235,7 @@ def _plotVarWithFlags(
     if history:
         for i in flags_hist.columns:
             # catch empty but existing history case (flags_meta={})
-            if len(flags_meta) == 0:
+            if len(flags_meta[i]) == 0:
                 continue
             scatter_kwargs.update({"label": flags_meta[i]["func"].split(".")[-1]})
             flags_i = flags_hist[i].astype(float)