__WEB_WIDGETS configuration is now done within the component's bld.inf files, not the top/mid level bld.infs
<?xml version="1.0"?>
<!DOCTYPE SystemDefinition SYSTEM "sysdef_1_4_0.dtd"
[ <!ENTITY layer_real_source_path "sf/app/webuis" > ]>
<SystemDefinition name="webuis" schema="1.4.0">
<systemModel>
<layer name="app_layer">
<module name="webuis">
<unit unitID="browsing_domain.webuis" mrp="" bldFile="&layer_real_source_path;/group" name="webuis"/>
</module>
</layer>
</systemModel>
</SystemDefinition>