Inappropriate background scaling on newly-enabled monitor

[Aaron Bentley]

When I enable my 1080p monitor via nvconfig or disper, the wallpaper image is fuzzy, and looks like a scaled-up version of the image on the existing 1366x768 monitor, even though the source image has greater resolution. I've used the "The Forbidden City" wallpaper from Ubuntu Precise as an example. It also occurs with my personal wallpapers.

The problem can be fixed by re-selecting the same wallpaper.

The attached images are crops of "The Forbidden City":
"rescaled.png": The way the wallpaper image looks on my 1080p monitor immediately after enabling

"orig-monitor.png": The way the wallpaper image looks on my 1366x768 monitor

"re-selected": The way the wallpaper image looks on my 1080p monitor after re-selecting it. (i.e. the way it should look immediately after enabling)

[Bilal Akhtar (bilalakhtar)]

Not sure if the background is drawn by Unity or not, but anyway, which version of Ubuntu are you using, and which version of Unity?

[Aaron Bentley (abentley)]

Ubuntu Precise, unity 5.12-0ubuntu1.1

[Bilal Akhtar (bilalakhtar)]

I confirmed it, Unity doesn't draw the wallpaper. It's either gnome-session that does it, nautilus, or lightdm.

[Sebastien Bacher (seb128)]

gnome-session has nothing to do with wallpaper, set as invalid, could be an nvidia driver issue...

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[md_5 (md-5)]

Don't think this is a driver issue, I think Nautilus is failing to handle resolution changes for display modes such as zoom.