I use -keep-all-type-selectors since my simple application loads a lot of complex modules.
However, I'm still seeing lots of warnings such as "The CSS type selector 'mx.controls.AdvancedDataGrid' was not processed..."
And I indeed get issues with the components listed in the warnings. In particular, only styles that were not already defined in data_management.css will be picked. Other components such as TextInput work perfectly.