1204694 - text disappears or appears scrambled when "Spell Check As You Type" is enabled

Status: NEW

(Core :: Graphics: Text, defect)

Description

[S. Christian Collins]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0
Build ID: 20150826185918

Steps to reproduce:

I made a video showing this bug here: https://youtu.be/ybkVPSfiNJs

Steps to reproduce:
1) In a new compose window, type a continuous line of text that spans two lines in the window. Put a misspelled word near the beginning of the first line and another one at the end of the second line.
2) Make sure "Options" -> "Spell Check As You Type" is enabled. You should see the red squiggle underneath the two misspelled words.
3) Resize the window horizontally (either direction) so that the word wrap changes (all text should still be on two lines).
4) Double-click to select the first misspelled word.
5) Click at the end of the second line.


Actual results:

Depending on the text entered and the resize operation, the text in the second line will either partially disappear, completely disappear, or get shifted over visually. I say "visually", because even though the text appears to be missing/misaligned, highlighting where the text should be will cause it to appear again.


Expected results:

The text shouldn't disappear/become scrambled.

I should note that this bug happens on my laptop, but not my desktop, so it's possibly related to graphics card drivers. Here are the technical details of my two systems:

** Laptop **  <-- the bug occurs on this system
OS: Kubuntu 14.04 64-bit w/ KDE SC 4.13.3
PC: HP Pavilion m6-1035dx
CPU/GPU: AMD A10-4600M APU with Radeon HD 7660G Graphics
RAM: 6GB DDR3 800 MHz
Linux Kernel: 3.16.0-49-generic
Video Driver: open-source Radeon driver
Screen Resolution: 1366 x 768

** Desktop **  <-- the bug does not occur on this system
OS: Kubuntu 14.04 64-bit w/ KDE SC 4.13.3
Motherboard: ASRock X58 Extreme3 (Intel X58 chipset)
CPU: Intel Core i7 930 (2.8 GHz quad-core)
RAM: 12GB DDR3
Video: NVIDIA GeForce 7900 GS w/ 256 MB RAM (PCI Express)
Linux Kernel: 3.13.0-63-generic
NVIDIA video driver: 304.125
Screen #1 Resolution: 1280 x 960 @ 100 Hz
Screen #2 Resolution: 1280 x 1024 @ 75 Hz

Comment 1

[:aceman]

Yes, I have also seen this frequently but also on Firefox. I assume this is a rendering bug in Gecko layout engine and/or the interaction with graphics driver/X server. It happens to me for at least a year.
Yes, I also see this on an AMD GPU with mesa drivers (always the latest, often from git).

Comment 2

[Milan Sreckovic [:milan] (needinfo for best results)]

What's the graphics section of about:support on the system (laptop) that shows the error?

Comment 3

[:aceman]

Mine is:

Graphics
Adapter Description	X.Org -- Gallium 0.4 on AMD RV710 (DRM 2.42.0, LLVM 3.7.0)
Asynchronous Pan/Zoom	none
Device ID	Gallium 0.4 on AMD RV710 (DRM 2.42.0, LLVM 3.7.0)
Driver Version	3.0 Mesa 11.1.0-devel (git-f7ca52d)
GPU Accelerated Windows	0/1 Basic (OMTC)
Supports Hardware H264 Decoding	No;
Vendor ID	X.Org
WebGL Renderer	X.Org -- Gallium 0.4 on AMD RV710 (DRM 2.42.0, LLVM 3.7.0)
windowLayerManagerRemote	true
AzureCanvasBackend	cairo
AzureContentBackend	cairo
AzureFallbackCanvasBackend	none
AzureSkiaAccelerated	0
CairoUseXRender	1

X.Org version is 1.16.4

I've recently upgraded to LLVM3.7 so will see if it makes a difference (radeon driver uses LLVM internally for generating GPU commands).

Comment 4

[S. Christian Collins]

Mine is:

Graphics
Adapter Description	X.Org -- Gallium 0.4 on AMD ARUBA
Asynchronous Pan/Zoom	none
Device ID	Gallium 0.4 on AMD ARUBA
Driver Version	3.0 Mesa 10.1.3
GPU Accelerated Windows	0/1 Basic (OMTC)
Supports Hardware H264 Decoding	false
Vendor ID	X.Org
WebGL Renderer	X.Org -- Gallium 0.4 on AMD ARUBA
windowLayerManagerRemote	true
AzureCanvasBackend	cairo
AzureContentBackend	cairo
AzureFallbackCanvasBackend	none
AzureSkiaAccelerated	0

Comment 5

[:aceman]

I can confirm the problem is still there with LLVM 3.7, X.Org 1.17 (gtk2, gtk3, pango, cairo up to date (from the distro)).

Comment 6

[u279076]

One thing I failed to notice in your first comment was that the Linux kernel on your laptop is a newer version than that of the desktop where this bug does not reproduce. I'm wondering if you could update your desktop to the same kernel to remove that as a variable. My apologies if you've already done that and I missed it somewhere.

Thanks

Comment 7

[S. Christian Collins]

I upgraded my desktop (temporarily) to the newer kernel (the Paragon NTFS driver doesn't yet support it), but the bug still doesn't happen on my desktop. Here is the about:support info from my desktop:

Adapter Description	NVIDIA Corporation -- GeForce 7900 GS/PCIe/SSE2
Asynchronous Pan/Zoom	none
Device ID	GeForce 7900 GS/PCIe/SSE2
Driver Version	2.1.2 NVIDIA 304.128
GPU Accelerated Windows	0/1 Basic (OMTC)
Supports Hardware H264 Decoding	false
Vendor ID	NVIDIA Corporation
WebGL Renderer	NVIDIA Corporation -- GeForce 7900 GS/PCIe/SSE2
windowLayerManagerRemote	true
AzureCanvasBackend	cairo
AzureContentBackend	cairo
AzureFallbackCanvasBackend	none
AzureSkiaAccelerated	0