When printing in landscape mode, it still cuts off the page as if it were printing in portrait mode. If you visit http://www.e-mart.net/printbug.htm and set the printing for landscape mode, you will see the right half of the screen cut off where it normally is in portrait mode. I have tested this under the WIN32 build (WinNT) using three different printers (including laser and inkjet. I'm also running the the M11 release build.
This is basically that: Landscape is not supported. *** This bug has been marked as a duplicate of 20880 ***
[bugday] verified as duplicate. landscape mode not supported.