Tikinewt problem with help button in search_box

The advanced search help button in module search_box is malfunctioning in the Tikinewt theme in most cases. Instead of opening a shadowbox with the help content, it does nothing.

It only works properly in Tikinewt if the floating help (Big Blue Help Button/BBHB) is displayed. For some reason, the BBHB only displays when first placing a page into edit mode (disappears after previewing).

By contrast, in the strasa theme, the search_box help button works consistently, regardless of whether the BBHB feature is even enabled.

This problem has been replicated on XP/IEv6, Vista/IEv7, Vista/FFv?.