254806 - autoscroll origin mark remains visible when it should not be

Status: VERIFIED DUPLICATE of bug 240363

(Firefox :: General, defect)

Description

[Matus Horvath]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040707 Firefox/0.8
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040707 Firefox/0.8

Sometimes while browsing, when I use the middle mouse button to autoscroll a
page, (or when I click the middle mouse button to open a link in new tab), and
some other page opens itself in a new tab at the same time (e.g. as a result of
an popup ad), the autoscroll mark remains visible but not operational on all
tabs in current window.

When this happens, the whole browser works just as usual, the only difference is
that on all tabs in current window, there is a grey rectangle with arrows (see
attached screenshot) as if you were autoscrolling (but you are not). You can
actually display a second autoscroll origin mark if you press the middle mouse
button again (then you have one real mark and one broken). 

If you scroll any tab, the mark moves with page contents, if you scroll it
outside of view, you just got rid of it for current tab, but if you switch to
another tab and back, you get it back on the same (window) coordinates as
before. If you open a new tabs, the mark sometimes appears on them and sometimes
not. If you open a new window, the mark seems to stay only in the original one.

Reproducible: Couldn't Reproduce
Steps to Reproduce:
This happened to me like three or four times, but I cannot reproduce the bug,
though I tried hard. It occurs when you use the middle mouse button a lot while
opening a lot of windows with popups at the same time. I am sorry, but I cannot
find any better way to reproduce it.
Actual Results:  
A gray box with a circle, a dot in the middle and four arrows (a.k.a. the
autoscroll origin mark) appeared on all tabs in current Firefox window. It
cannot be used to scroll or to do anything else.

Expected Results:  
It shouldn't display a visual glitch which blocks a square centimeter of every
page contents and can only be permanently removed by restarting Firefox.

Perhaps applies only to Windows.
I have Tabbrowser Extensions installed, but I'd say that is not the problem.

This bug is perhaps somehow related to how tab contents are redrawn without
re-rendering them (since the mark goes away when scrolled out of view and then
back). Perhaps something remembers there should be a mark drawn on some absolute
(window) location and then by mistake does not 'forget' it. (Disclaimer: I am
not a Firefox developer, just guessing.)

Comment 1

[Matus Horvath]

Attachment: how it looks like - initial

Comment 2

[Matus Horvath]

Attachment: how it looks like - after scrolling down

Comment 3

[Matus Horvath]

Attachment: how it looks like - even more scrolling

Comment 4

[Matus Horvath]

Attachment: how it looks like - scrolled out of view and back again

the mark has disappeared

Comment 5

[Matus Horvath]

Attachment: how it looks like - switch to another tab

the mark is there again, on the same window coordinates

Comment 6

[Matus Horvath]

Attachment: how it looks like - switch back from another tab

the mark re-appears

Comment 7

[Matus Horvath]

Attachment: how it looks like - partly scrolled out of view

Comment 8

[Matus Horvath]

Attachment: how it looks like - part of mark disappeared

Comment 9

[Matus Horvath]

Attachment: how it looks like - two autoscroll marks

Comment 10

[Matus Horvath]

Comment on attachment 155509 [details]
how it looks like - part of mark disappeared

one is real (with two arrows), the other one should not be there

Comment 11

[Robert Parenton]

Can you reproduce this with the latest nightly of Firefox with a clean profile
and no extensions?

Comment 12

[Robert Parenton]

*** This bug has been marked as a duplicate of 240363 ***