create a new web content from control panel, in categorization select a category already defined and publish the web content.
add an asset publisher portlet into page, configure it to filter by category selected above and save.
the asset publisher portlet now displays the web content.
using "edit" action in asset publisher to modify the web content. the selected category is lost, so if i save i lose the information.
it works correctly when the web content is managed via control panel