1164588 - Choopy menu/bookmarks doorhanger animation after update to Firefox 40

Status: RESOLVED DUPLICATE of bug 1122526

(Firefox :: Untriaged, defect)

Description

[[:philipp]]

Attachment: comparison.gif

after updating from firefox 39 to 40 i've noticed that the dropdown animation when pressing the menu or bookmarks button is much more choppy than before. during the animation the text & icons are heavily pixelated and they get sharp just once the animation finishes.

i've narrowed down this regression window:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=4fe763cbe196&tocha
nge=ab0490972e1e

my graphics section from about:support:
Adapter Description	Intel(R) HD Graphics
Adapter Drivers	igdumd64 igd10umd64 igdumdx32 igd10umd32
Adapter RAM	Unknown
Asynchronous Pan/Zoom	none
ClearType Parameters	Gamma: 2200 Pixel Structure: R ClearType Level: 100 Enhanced Contrast: 100
Device ID	0x0042
Direct2D Enabled	true
DirectWrite Enabled	true (6.2.9200.16571)
Driver Date	1-30-2013
Driver Version	8.15.10.2993
GPU #2 Active	false
GPU Accelerated Windows	1/1 Direct3D 11 (OMTC)
Subsys ID	306a17aa
Supports Hardware H264 Decoding	true
Vendor ID	0x8086
WebGL Renderer	Google Inc. -- ANGLE (Intel(R) HD Graphics Direct3D9Ex vs_3_0 ps_3_0)
windowLayerManagerRemote	true
AzureCanvasBackend	direct2d 1.1
AzureContentBackend	direct2d 1.1
AzureFallbackCanvasBackend	cairo
AzureSkiaAccelerated	0