217277 - incomplete focus (or activation) before docshell hierarchy is built

Status: NEW

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[Dan M]

Crash bug 170693 seems to have been fixed by checking whether the window given
WindowWatcher as the new active window is a genuine, top-level window. This
implies that nsFocusController sometimes attempts to set the active window
before the window's docshell hierarchy has been built up all the way to the
root. (See bug 170693 comment 23).

With the crash fix checked in (it is), we know that WindowWatcher's active
window reference is now sometimes incorrect. This is not a fatal problem, but it
could leak to irksome issues finding the correct parent for dependent windows.
Perhaps there are other side effects as well. Hard to say, since no one with a
debugging build has ever been able to reproduce this problem.

To make the focus-or-activation situation well, nsFocusController wants at least
to note when window activation fails (wwatch->SetActiveWindow in
nsFocusController::UpdateWWActiveWindow() will return an error code), and
schedule another attempt to set the active window later, once the entire
docshell hierarchy has loaded.