UGENE hangs on sequence graph plotting

1. Open file "data/samples/Genbank/sars.gb"
2. Select

{ Graphs -> GC Content (%) }

on the sequence view toolbar
Expected state: the graph has been plotted
3. Call context menu on the graph and choose

{ Graph -> Graph settings... }

Expected state: the "Graph Settings" dialog has appeared
4. Set

{ Window : 10000; Steps per window: 10000 }

and accept the dialog
Expected state: graph plot task has started. the graph is plotted after it finishes.
Current state: UGENE is hanging for about 20 seconds and then plots the graph