115198 - clientX and clientY coordinates are incorrect

Status: VERIFIED FIXED

(Core :: DOM: Events, defect)

Description

[Brian Ryner (not reading)]

Any time a frame on a web page has a view that has its own widget, any mouse
events within that frame get incorrect clientX and clientY coordinates if the
page is scrolled.  Here's why:

Widgets keep their stored bounds in an nsRect (see nsWindow.cpp).  The position
of this rect is only modified via calls to SetBounds() or Move().  As the user
scrolls, we don't update the bounds, so they continue to reflect the position
when the page was first reflowed.  The code that computes clientX and clientY
relies on these bounds reflecting the position relative to the visible viewport.
 This is automatic on Windows, because the OS is queried for the widget's
current position.  On mac, the bounds remain correct because the bounds for
child windows are updated when nsWindow::Scroll is called.

Comment 1

[Brian Ryner (not reading)]

Attachment: test case

To see the bug, load the test case and scroll the page down a bit.  Now move
the mouse from the page into the inner div and watch clientY jump.

Comment 2

[Brian Ryner (not reading)]

Attachment: patch to update child window bounds when scrolling

Comment 3

[Christopher Blizzard (:blizzard)]

Comment on attachment 61712 [details] [diff] [review]
patch to update child window bounds when scrolling

r/sr=blizzard

Nice catch!

Comment 4

[Brian Ryner (not reading)]

checked in.

Comment 5

[Pierre Chanial]

imho, bug 33226 should be duped against this one.

Comment 6

[Vladimir Ermakov]

verifying on build 2002-01-04-08-trunk linux RedHat
and build 2002-01-04-03-trunk windows 98