Taxonomy picker "palette" type styling broken

If a taxonomy field is configured with "taxonomy.type=palette" as opposed to "tree" (the default), the taxonomy picker dialog shows a palette, a.k.a. shootbox.

The styling thereof is broken, apparently the CSS expects a table but the HTML is not a table (any more, maybe the Wicket 9 upgrade?):

PS the boxes are even higher that above by default, leaving the viewport of the dialog.