The sign-in panel is positioned absolutely, so it grows the iframe without
growing the document: `useDropdown` measures the panel itself and posts the
sum, and a ResizeObserver on the panel keeps that number current while it is
open. Closing it resizes no box anything watches. The panel observer goes with
the element, and the document observer in `Root` sees nothing, because the
document height never changed in the first place. Nothing then tells the parent
to come back down, so the iframe keeps the open panel's height and the
embedding page carries a hole under the widget for as long as the reader stays
on it.
The effect's cleanup now reports the height, with no element, so the number is
the document's own. That is the one place both close paths reach: the click
inside the widget, and the clickOutside message the host page posts when the
reader clicks anywhere else.
TestGeometry_HeightFollowsTheAuthPanelAndTheTextarea covers this and has been
intermittently green: whether the frame comes back down without the fix depends
on timing, and it fails on every run here while CI has been passing. The unit
test fails with the cleanup reverted.
Dmitry VerkhoturovandGitHub
250e8ad925