I've tried both the 3.0 stable and the 3.0 dev.
Expected behavior: Checking "force render" on left and middle preface region will make them behave as if they contained the invisible debugging block - that is, fill the columns - so that when there's a block in the right preface region, it will actually be at the right/
Actual behavior: Left and middle preface divs are present in page source but contain no element or content. These regions collapse and the right preface block floats all the way to the left, so it looks like it's actually in the left preface region.
As soon as there's some actual content (element, printable character, whatever) in the region, it works. So I'm working around this problem by using region--preface_*.tpl.php to put a non-breaking space into the region if there's not any other content.
I'm setting this to "User Interface" and "Support Request" in case this all stems from some mis-understanding on *my* part about how the "force render" feature is supposed to work.
FAILED: [[SimpleTest]]: [MySQL] Unable to apply patch omega-1295128_0.patch. Unable to apply patch. See the log in the details link for more information. View
FAILED: [[SimpleTest]]: [MySQL] Unable to apply patch omega-1295128.patch. Unable to apply patch. See the log in the details link for more information. View