Emilio Cobos Álvarez
23778bbea2
In this test-case, rootFrameToSelect is the inner editor's frame, but contentToSelect is the textarea, which is an ancestor. So we go from `<textarea>` all the way to the root frame finding scrollable frames which is not the intended behavior. Instead, we check nsLayoutUtils::IsProperAncestorFrame to make sure that we walk correctly. Differential Revision: https://phabricator.services.mozilla.com/D310594