I've had problems browsing Chowhound with Windows Mobile 5 (built-in IE browser) from day one, but the collapsible outline has made it a lot worse, since the expand icons and Expand All buttons are among the many that don't work. Clicking does nothing, no action, no error.
The "advanced" search link is also dead.
The Post New Topic and Post My Reply buttons don't appear at all.
Chowhound's really a natural for mobile devices, shame it's not more usable.