The Greeter sometimes does not display the GNOME Shell top bar

On 3.0~beta4. The desktop background was black and the corners of the greeter’s window were square. Only relevant logs I could find:

May 16 11:33:15 amnesia gdm-shell-tails.desktop[3502]: X Error of failed request:  XI_BadDevice (invalid Device parameter)
May 16 11:33:15 amnesia gdm-shell-tails.desktop[3502]:   Major opcode of failed request:  131 (XInputExtension)
May 16 11:33:15 amnesia gdm-shell-tails.desktop[3502]:   Minor opcode of failed request:  59 ()
May 16 11:33:15 amnesia gdm-shell-tails.desktop[3502]:   Device id in failed request: 0x27c
May 16 11:33:15 amnesia gdm-shell-tails.desktop[3502]:   Serial number of failed request:  253
May 16 11:33:15 amnesia gdm-shell-tails.desktop[3502]:   Current serial number in output stream:  253

… immediately after X.Org detected the “spice vdagent tablet”. And indeed, there’s no running gnome-shell process for the GDM session. I wonder if this might be related to set-cursor.py.

The keyboard layout and admin password I’ve set was successfully applied.

Related issues

• Related to #12364 (closed)

Original created by @intrigeri on 12548 (Redmine)