Ultimate Taxonomy Manager doesn't show combobox

hi, just installed the Ultimate Taxonomy Manager plugin (2.0), but when I set combobox for a new taxonomy, then it doens’t show it in the post editing page.

I created a custom taxonomy, flagged “article” and then set “Show as ComboBox” to “true” value.
Then i added some custom fields to the taxonomy, and here i tried many times with different field type (but one type at once per taxonomy) and then, opening the new post page, che custom combobox doesn’t show up.

It showed up the very first times, until i added some data. But anyway I also tried to uninstall the plugin and drop the tables wp_taxonomyfield and wp_taxonomymeta, but nothing has changed.
What have I to do?