185293 - onMouseOver event doesn't fire when page loads with mouse in area

Status: NEW

(Core :: DOM: Events, defect, P5)

Description

[Chris Abbey]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021116
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021116

If when the page loads the mouse is inside the area covered by an onMouseOver
event, the event is not fired unless/untill the mouse (or area) moves. Just one
pixel of movement is sufficient, as long as the pixel that the mouse lands in is
also inside the area.

OnMouseOut events do fire when the mouse leaves the area, which can cause poorly
coded web pages to fall apart. The case that brought this to my attention was an
intra-net app that relied on onMouseOver to push an entry onto a stack, that
onMouseOut poped... except that the stack was empty and the results were a mess.


Reproducible: Always

Steps to Reproduce:
Using the referenced URL:

1. put your mouse on either the prev or next icons
2. note that onMouseOver fired and changed the colour of the button
3. click, but don't move the mouse (this is a LOT easier if you have a
trackpoint keyboard, such as on a thinkpad)
4. wait for the next page to load.
5. observe that the button never changes (event never fires)
6. move the mouse just a pixel to either side (remaining within the image)
7. note that the event fires and the script changes the image
Actual Results:  
event does not fire, image does not change on page load.

Expected Results:  
event should have fired, causing the image to be changed.

Moz was built from cvs MOZILLA_1_2_BRANCH
checkout finish: Wed Dec 11 22:34:58 CST 2002

Comment 1

[Andrew Schultz]

Attachment: stacktrace

Assertion failure: count, at nsXMLContentSink.cpp:1310

Comment 2

[Andrew Schultz]

Comment on attachment 109287 [details]
stacktrace

sorry, wrong bug

Comment 3

[Vladimir Ermakov]

Confirming. 

Comment 4

[Nathan Kurz]

Bug #193166 (Mouseover event generated if element created under mouse) might be
related to this, although it is somewhat the opposite of this bug.

Comment 5

[José Jeria]

Dupe of bug 50511?

Comment 6

[Chris Abbey]

possibly related, will leave it up to Saari to decide if they're dups (both are
assigned to Saari).

From reading 193166 and 50511, the two might be related, but I'm unable to
reproduce 193166; while I can reproduce this still. (trunk cvs as of 10-15)

Comment 7

[Kevin Ar18]

*** Bug 255815 has been marked as a duplicate of this bug. ***

Comment 8

[Magnus Kristiansen]

Attachment: Testcase

Bug is still active in Mozilla 1.7.5
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041217

The bug (mouseover not happening until you move the mouse) seems like it could
be somehow related to Bug 252249 (mouseout not happening until you move the
mouse) The testcase shows both mouseout and mouseover events.

As mentioned already, when reloading or loading a new page the expected
mouseover on new page never happens. Bug 2522249 suggests it could also happen
with tab switching. I don't use tabs much, but the bug does happens when
alt-tabbing to a window that covers the current cursor position. This can be
done after a regular mouseover, or before a mouseover by using this very bug
and not moving the cursor before using alt-tab.
* After mouseover, alt-tab out and back: mouseout occurs properly, but no
mouseover happens until I move the cursor (the bug)
* After mouseover, alt-tab out, move cursor, back: mouseout and mouseover occur
properly
* Before mouseover, alt-tab out and back: no mouseout (as expected, cannot
happen before mouseover) and no mouseover (the bug)
* Before mouseover, alt-tab out, move cursor, back: no mouseout, but mouseover
when page regains focus (both as expected)

The nightly build for Mozilla 1.8b2 also has the bug, as well as another: it
doesn't generate any mouseout events at all when leaving window with alt-tab.
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050226

Comment 9

[Firefox Bug Husbandry Bot]

Bulk priority change, per :mdaly