1249986 - Duplicated screen partially shown when hovering link with peculiar tooltip title

Status: NEW

(Core :: Graphics, defect, P3)

Description

[nicolas m]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:46.0) Gecko/20100101 Firefox/46.0
Build ID: 20160221004008

Steps to reproduce:

I hovered with my cursor the link in this tweet:
https://twitter.com/raphaelbastide/status/698467026566774784

Using Firefox 46, Ubuntu 15.10, Gnome 3.18.2, and X.org 1.17.2.


Actual results:

My whole screen is duplicated and partially reproduced under the cursor.

See this video:
https://twitter.com/nclm_/status/701444075841519617

and the attached video for a simpler test case. 



Expected results:

Nothing special.

Comment 1

[nicolas m]

Attachment: HTML test case

Comment 2

[nicolas m]

Attachment: OGV video of the bug happening on the test case

Comment 3

[nicolas m]

As the test case shows, the issue comes from the extra long (~2000 chars) title property on the link.

However, replacing these characters by 2000 copies of the letter ‘a’ doesn’t trigger the bug.

Therefore, something in this particular series of characters leads to that improbable result.

Comment 4

[Kanchan Kumari QA]

I couldn't reproduce this issue using original URL or test case on following version.
Name     Firefox
Version     47.0a1
Build ID     20160222030212
Update Channel     nightly
User Agent     Mozilla/5.0 (X11; Linux x86_64; rv:47.0) Gecko/20100101 Firefox/47.0
OS     Linux 4.2.0-16-generic x86-64Name 	Firefox

Can you please retest this on the latest nightly build.

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

I can reproduce, but this isn't any DOM bug.

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

(nor event handling)

Comment 7

[Karl Tomlinson (:karlt)]

kwin shows a short wide completely black opaque tooltip with compositing enabled.
With compositing disabled, the light text on the tooltip is visible.