http://bugs.winehq.org/show_bug.cgi?id=28604
--- Comment #14 from Yuri Khan yurivkhan@gmail.com 2011-11-22 12:06:51 CST --- Nice to know. Thank you for taking the time to investigate this.
So, before the implementation of polylines, all work happened on the X11 server side, and after polygons all work will be done on the application side, but for now they polylines are drawn app-side and polygons server-side, causing lots of roundtrips.
And, I can immediately imagine a reason why polylines might be interleaved with polygons: Railroads are drawn as strings of almost rectangular sections, one solid, one hollow, repeating for the whole length of the railroad.