702537 - Performance issue while dragging objects over floating borders of certain styles

Status: UNCONFIRMED

(Firefox :: General, defect)

Description

[dpatti]

Attachment: moz-border-bug.html

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.36 Safari/535.7

Steps to reproduce:

I have attached a file that will reproduce this problem. Move your mouse around the screen to drag the box.


Actual results:

You will notice how the black box lags behind and CPU usage goes way up. If you edit the CSS to change the border style from ridge to solid, the problem disappears. Additionally, if you remove the "float: left", the problem also disappears.

Other styles that I have found to cause lag include: groove, inset, and outset.
I would also like to note that this occurs on both Nightly (11.0a1) and Release (8.0).


Expected results:

There should be no drastic decrease in performance as when you set the border to solid.

Comment 1

[dpatti]

I would also like to note that floating is not a full restriction. I went back and attempted to position it absolutely, and while the slow down was not as noticeable, it was certainly still not as smooth as with solid borders.