In GWT 2.1.0.M2 the options "-style pretty" couldn't be recognized

I am using GWT eclipse plugin and try to add option "-style pretty" inside arguments tab of debug configuration window in eclipse. But after click debug it just prompts "Unknown argument: -style". I used to use webcreator to create gwt app. this is my first time to use plugin and i am not sure i put it into the right place or gwt 2.1.0.M2 just doesn't开发者_开发知识库 support this option (which is wired). Please help me thanks in advance.

Just found out when you right click the project and choose google->compile, a window will show up and there is a drop down list box which you could choose style level such as pretty or detailed. Sometimes the easy thing is hard to find......