PinHint's first-visit pill sits at z-index 2147482000, so with MapInfo's scrim at 1000 the pill floated
bright and clickable over the dimmed backdrop while the popup was open (gospel; measured on the live
build: the pill's centre hit the pill, not the scrim, on Cities). The scrim goes to 2147483000; the
dialog is its child, inside the scrim's stacking context, so it stays on top of the scrim. The root fix
is the top layer (<dialog>.showModal()), carded.