xforms-hint event seems not to happen on any form control

The attached form shows each of the xform controls with action handlers to show an xf:message for both xforms-help and xforms-hint events. Only the xforms-help event seems to happen (and only on certain controls, but that should be another issue).

In the attached form, putting the mouse over a control that has an xf:hint (all controls in the form) should cause a xforms-hint event to occur.