STR 1. Open UITest app, switch to CopyPaste tab. 2. Long tap to select a word. 3. Scroll the page Expected result: Selection carets should remain on screen. Actual result: Selection carets are missing.

NotifyAsyncPanZoomStarted/Stopped only dispatch to top level nsDocShell. So if selection carets are inside iframe then those carets never receive NotifyAsyncPanZoomStarted/Stopped event and carets position never get updated. This patch dispatch this event to nsDocShell's child as well.

After applying this patch, SelectionCarets shows correctly after scrolling in the UITest app.

Comment on attachment 8510911 [details] [diff] [review] also-dispatch-to-docshell-child Review of attachment 8510911 [details] [diff] [review]: ----------------------------------------------------------------- ::: docshell/base/nsDocShell.cpp @@ +3120,5 @@ > + uint32_t n = mChildList.Length(); > + kids.SetCapacity(n); > + for (uint32_t i = 0; i < n; i++) { > + kids.AppendElement(do_QueryInterface(ChildAt(i))); > + } Why are we using this temporary array?

(In reply to Robert O'Callahan (:roc) (Mozilla Corporation) from comment #3) > Comment on attachment 8510911 [details] [diff] [review] > also-dispatch-to-docshell-child > > Review of attachment 8510911 [details] [diff] [review]: > ----------------------------------------------------------------- > > ::: docshell/base/nsDocShell.cpp > @@ +3120,5 @@ > > + uint32_t n = mChildList.Length(); > > + kids.SetCapacity(n); > > + for (uint32_t i = 0; i < n; i++) { > > + kids.AppendElement(do_QueryInterface(ChildAt(i))); > > + } > > Why are we using this temporary array? I just followed nsDocShell::FirePageHideNotification. Maybe we don't need this temporary array here. I'll attach new patch later.

Remove temporary array.

(In reply to Morris Tseng [:mtseng] from comment #4) > I just followed nsDocShell::FirePageHideNotification. Maybe we don't need > this temporary array here. I'll attach new patch later. FirePageHideNotification needs a temporary array because it runs arbitrary JS which can alter the docshell tree. I don't think your notifications have that problem.

try run https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=6dcfb21ad5c8

Hi Morris, this patch failed to apply: Hunk #1 FAILED at 883 1 out of 1 hunks FAILED -- saving rejects to file layout/base/SelectionCarets.cpp.rej patch failed, unable to continue (try -v) patch failed, rejects left in working dir errors during apply, please fix and refresh also-dispatch-to-docshell-child could you take a look? Thanks!

Rebased. This patch should be applied.