Sometimes opens in a tiny window at top-left and does not re-size

openQA GNOME tests quite often encounter a situation where g-i-s, running in its "no users created yet" mode on first boot, runs as a tiny window at top left of the desktop and never resizes to a readable size. It looks like this:

The VMs that openQA tests run in are qemu VMs with 1024x768 displays, using the virtio graphics device/driver.

This doesn't happen every time, it's kinda intermittent. At a rough guess it happens one in every four or five times. When the bug doesn't happen, the g-i-s window takes up the whole screen outside of the top bar.

I do wonder if this might be the same as #97 (just behaving a bit differently at different resolutions), but filing separately for now.