I found out that the problem is the <!doctype html> declaration, ie Im using “standards” mode.
I just noticed then, that the SmartGWT_Quick_Start_Guide.pdf suggests to use browser compatibility mode. This scares me a bit.
Compatibility mode is historically recommended as giving the best appearance and performance across all browsers, but it shouldn’t be required for pixel perfect appearance in modern browsers. If you’re seeing this kind of thing with the latest code / a current browser, we’d like to know about it.