Your system information

• Steam client version (build number or date): 1686092969 (Wed, Jun 7 12:51 AM UTC -08:00)
• Distribution Debian unstable/sid
• Opted into Steam client beta?: Yes
• Have you checked for system updates?: Yes
• System information: gist
• Steam Runtime System Information: gist

Please describe your issue in as much detail as possible:

Whenever a window or a notification popup is created when there is no display available, the steam client "crashes". Actually I think it is not a crash, but the client turns into an unusable state.

I have three displays setup, but I suspect the number of display are irrelevant. Whenever I go AFK I turn off my monitors, when I return to my desktop and turn back on the monitors, most of the times the steam client is "crashed".

Here is a normal xrandr output:

$ xrandr
Screen 0: minimum 8 x 8, current 5760 x 1080, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 530mm x 300mm
   1920x1080     60.00*+  59.94    50.00
   1600x1200     60.00
   1600x900      60.00
   1280x1024     75.02    60.02
   1280x720      60.00    59.94    50.00
   1152x864      75.00
   1024x768      75.03    60.00
   800x600       75.00    60.32
   720x576       50.00
   720x480       59.94
   640x480       75.00    59.94    59.93
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected 1920x1080+3840+0 (normal left inverted right x axis y axis) 530mm x 300mm
   1920x1080     60.00*+  59.94    50.00
   1600x1200     60.00
   1600x900      60.00
   1280x1024     75.02    60.02
   1280x720      60.00    59.94    50.00
   1152x864      75.00
   1024x768      75.03    60.00
   800x600       75.00    60.32
   720x576       50.00
   720x480       59.94
   640x480       75.00    59.94    59.93
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 530mm x 300mm
   1920x1080     60.00*+  59.94    50.00
   1600x1200     60.00
   1600x900      60.00
   1280x1024     75.02    60.02
   1280x720      60.00    59.94    50.00
   1152x864      75.00
   1024x768      75.03    60.00
   800x600       75.00    60.32
   720x576       50.00
   720x480       59.94
   640x480       75.00    59.94    59.93
DP-5 disconnected (normal left inverted right x axis y axis)

And this is xrandr with two monitors powered off:

$ xrandr
Screen 0: minimum 8 x 8, current 5760 x 1080, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 disconnected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 0mm x 0mm
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected 1920x1080+3840+0 (normal left inverted right x axis y axis) 530mm x 300mm
   1920x1080     60.00*+  59.94    50.00
   1600x1200     60.00
   1600x900      60.00
   1280x1024     75.02    60.02
   1280x720      60.00    59.94    50.00
   1152x864      75.00
   1024x768      75.03    60.00
   800x600       75.00    60.32
   720x576       50.00
   720x480       59.94
   640x480       75.00    59.94    59.93
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
DP-5 disconnected (normal left inverted right x axis y axis)

My guess is that when creating a new chat window, a notification window, or any kind of new window, the steam client tries to obtain the displays available such as provided by randr and somehow it fails to create a new window and crashes.

Here is the desktop state whenever I turn back on the monitor:

Same, but with the steam client windows unstacked.

Looks like an independent window is created for every popup menu and stacked over the main client window.

I have attached several logs which include some debug on the crash:
steamui_html.txt
steamwebhelper.log
webhelper.txt

Steps for reproducing this issue:

1. Open steam
2. Turn off every monitor connected to the system
3. Send a chat message from another account
4. Turn back on the monitor and check the client crashed state

Other notes:

• It does not matter if you disable all notifications, it still crashes when creating a chat window from an incoming message.
• It does not matter if you enable or disable hardware acceleration options
• Stable client does not have this problem. I think the problem started with the new UI overhaul.