Unreal Engine freezes in fullscreen

[danebidev]

Welcome

• Yes, I'm using the latest major release or the current development version. These are the only supported versions.
• Yes, I've searched similar issues and discussions on GitHub and didn't find any.

Current Behavior

I'm not sure it's an i3 problem but I couldn't reproduce with any other wm so i'm asking here.
I just installed UE 5.4.1 and noticed that it seems to freeze completely when I start dragging any asset from the content browser and it only seems to happen when the window is in fullscreen.
UE draws a small tooltip when dragging so maybe it's failing to draw that. Also, if I exit fullscreen it starts working again.
I also tried with UE 5.1.1 but it has the same issue.
I'm using picom but the same issue happens without compositor.

Expected Behavior

UE shouldn't freeze when dragging in fullscreen.

Reproduction Instructions

1. Start UE5
2. Open any project (I've been trying in the example projects)
3. Enter fullscreen
4. Drag any asset from the content browser to the viewport

i3 version

Binary i3 version:  4.23-35-gcaf5b32d © 2009 Michael Stapelberg and contributors
Running i3 version: 4.23-35-gcaf5b32d (pid 939)
Loaded i3 config:
  /home/danebidev/.config/i3/config (main) (last modified: Fri 17 May 2024 11:41:29 PM CEST, 1056 seconds ago)

The i3 binary you just called: /usr/bin/i3
The i3 binary you are running: /usr/bin/i3

Config file

set $mod Mod4

font pango:Fira Mono 8

# Remove borders
for_window [class="^.*"] border pixel 0

# Gap size
gaps inner 15
gaps outer 5

# Use Mouse+$mod to drag floating windows to their wanted position
floating_modifier $mod

mouse_warping none

# move tiling windows via drag & drop by left-clicking into the title bar,
# or left-clicking anywhere into the window while holding the floating modifier.
tiling_drag modifier titlebar

# start a terminal
bindsym $mod+Return exec kitty

# kill focused window
bindsym $mod+c kill

# Rofi
bindsym $mod+p exec rofi -show drun -show-icons -icon-theme "Numix-Circle"

# Scrot
bindsym $mod+s exec sleep 0.5 && scrot -s '%Y-%m-%d_$wx$h.png' -e 'mv $f ~/Pictures/Screenshots'

# Lock
bindsym $mod+Shift+b exec i3lock

# change focus
bindsym $mod+h focus left
bindsym $mod+j focus down
bindsym $mod+k focus up
bindsym $mod+l focus right

# alternatively, you can use the cursor keys:
bindsym $mod+Left focus left
bindsym $mod+Down focus down
bindsym $mod+Up focus up
bindsym $mod+Right focus right

# move focused window
bindsym $mod+Shift+h move left
bindsym $mod+Shift+j move down
bindsym $mod+Shift+k move up
bindsym $mod+Shift+l move right

# alternatively, you can use the cursor keys:
bindsym $mod+Shift+Left move left
bindsym $mod+Shift+Down move down
bindsym $mod+Shift+Up move up
bindsym $mod+Shift+Right move right

# split in horizontal orientation
bindsym $mod+n split h

# split in vertical orientation
bindsym $mod+v split v

# enter fullscreen mode for the focused container
bindsym $mod+f fullscreen toggle

# change container layout (stacked, tabbed, toggle split)
bindsym $mod+q layout stacking
bindsym $mod+w layout tabbed
bindsym $mod+e layout toggle split

# toggle tiling / floating
bindsym $mod+Shift+space floating toggle

# change focus between tiling / floating windows
bindsym $mod+space focus mode_toggle

# focus the parent container
bindsym $mod+a focus parent

# focus the child container
bindsym $mod+d focus child

# Define names for default workspaces for which we configure key bindings later on.
set $ws1 "www"
set $ws2 "term"
set $ws3 "apps"
set $ws4 "misc1"
set $ws5 "misc2"
set $ws6 "misc3"
set $ws7 "misc4"
set $ws8 "misc5"
set $ws9 "misc6"
set $ws10 "misc7"

# switch to workspace
bindsym $mod+1 workspace $ws1
bindsym $mod+2 workspace $ws2
bindsym $mod+3 workspace $ws3
bindsym $mod+4 workspace $ws4
bindsym $mod+5 workspace $ws5
bindsym $mod+6 workspace $ws6
bindsym $mod+7 workspace $ws7
bindsym $mod+8 workspace $ws8
bindsym $mod+9 workspace $ws9
bindsym $mod+0 workspace $ws10

# move focused container to workspace
bindsym $mod+Shift+1 move container to workspace $ws1
bindsym $mod+Shift+2 move container to workspace $ws2
bindsym $mod+Shift+3 move container to workspace $ws3
bindsym $mod+Shift+4 move container to workspace $ws4
bindsym $mod+Shift+5 move container to workspace $ws5
bindsym $mod+Shift+6 move container to workspace $ws6
bindsym $mod+Shift+7 move container to workspace $ws7
bindsym $mod+Shift+8 move container to workspace $ws8
bindsym $mod+Shift+9 move container to workspace $ws9
bindsym $mod+Shift+0 move container to workspace $ws10

# reload the configuration file
bindsym $mod+Shift+c reload
# restart i3 inplace (preserves your layout/session, can be used to upgrade i3)
bindsym $mod+Shift+r restart
# exit i3 (logs you out of your X session)
bindsym $mod+Shift+e exec "i3-nagbar -t warning -m 'You pressed the exit shortcut. Do you really want to exit i3? This will end your X session.' -B 'Yes, exit i3' 'i3-msg exit'"

# resize window (you can also use the mouse for that)
mode "resize" {
        # These bindings trigger as soon as you enter the resize mode

        # Pressing left will shrink the window’s width.
        # Pressing right will grow the window’s width.
        # Pressing up will shrink the window’s height.
        # Pressing down will grow the window’s height.
        bindsym h resize shrink width 10 px or 10 ppt
        bindsym j resize grow height 10 px or 10 ppt
        bindsym k resize shrink height 10 px or 10 ppt
        bindsym l resize grow width 10 px or 10 ppt

        # same bindings, but for the arrow keys
        bindsym Left resize shrink width 10 px or 10 ppt
        bindsym Down resize grow height 10 px or 10 ppt
        bindsym Up resize shrink height 10 px or 10 ppt
        bindsym Right resize grow width 10 px or 10 ppt

        # back to normal: Enter or Escape or $mod+r
        bindsym Return mode "default"
        bindsym Escape mode "default"
        bindsym $mod+r mode "default"
}

bindsym $mod+r mode "resize"

# Autostart
exec --no-startup-id dex --autostart --environment i3
exec --no-startup-id dunst

exec_always "setxkbmap -model pc105 -layout us,it -option grp:alt_shift_toggle"

Linux distribution & Version

ArchLinux

Are you using a compositor?

picom

Logfile

https://logs.i3wm.org/logs/6283358514446336.bz2

[danebidev]

I think I found the issue though I'm not sure it's a problem with i3.
When you drag something in the content browser a small popup window appears:

The problem is that this popup is not just a tooltip drawn on the UE main window but an actual window and i3 changes focus to it. It seems that when the main window is in fullscreen the popup goes under the window and UE for some reason goes in a deadlock.
I searched and couldn't find any way to prevent UE from opening the window so I was hoping there was some way to fix this on i3's side. I tried the popup_during_fullscreen option but it didn't change anything.

[orestisfl]

Can you run `xprop` and click on the popup window when it shows up? Paste the output here.

…

On Sat, 18 May 2024, 14:35 danebidev, ***@***.***> wrote: I think I found the issue though I'm not sure it's a problem with i3. When you drag something in the content browser a small popup window appears: Screenshot.from.2024-05-18.13-54-19.png (view on web) <https://github.com/i3/i3/assets/57720273/4e6f18f7-2cc1-4b00-8b8a-db56e7219b88> The problem is that this popup is not just a tooltip drawn on the UE main window but an actual window and i3 changes focus to it. It seems that when the main window is in fullscreen the popup goes under the window and UE for some reason goes in a deadlock. I searched and couldn't find any way to prevent UE from opening the window so I was hoping there was some way to fix this on i3's side. I tried the popup_during_fullscreen option but it didn't change anything. — Reply to this email directly, view it on GitHub <#6057 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABMCZPTOFJDLKCZC5MBCZKLZC5DJ7AVCNFSM6AAAAABH43AEGOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDCMJYHAYTANBSGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[danebidev]

_NET_WM_DESKTOP(CARDINAL) = 4
I3_FLOATING_WINDOW(CARDINAL) = 1
XdndAware(ATOM) = BITMAP
_NET_WM_NAME(UTF8_STRING) = 
WM_NAME(STRING) = 
WM_PROTOCOLS(ATOM): protocols  WM_DELETE_WINDOW, WM_TAKE_FOCUS, _NET_WM_PING
_NET_WM_BYPASS_COMPOSITOR(CARDINAL) = 1
_NET_WM_WINDOW_TYPE(ATOM) = _NET_WM_WINDOW_TYPE_NORMAL
_NET_WM_STATE(ATOM) = _NET_WM_STATE_ABOVE, _NET_WM_STATE_SKIP_TASKBAR, _NET_WM_STATE_SKIP_PAGER
_NET_WM_PID(CARDINAL) = 84721
WM_LOCALE_NAME(STRING) = "C"
WM_CLASS(STRING) = "UnrealEditor", "UnrealEditor"
WM_HINTS(WM_HINTS):
		Client accepts input or input focus: False
		window id # of group leader: 0x1287391
WM_NORMAL_HINTS(WM_SIZE_HINTS):
		user specified location: 960, 540
		program specified minimum size: 1 by 1
		program specified maximum size: 1 by 1
WM_CLIENT_MACHINE(STRING) = "archlinux"
_MOTIF_WM_HINTS(_MOTIF_WM_HINTS) = 0x2, 0x0, 0x0, 0x0, 0x0

[orestisfl]

I tried the popup_during_fullscreen option but it didn't change anything.

That's because the window is missing the WM_TRANSIENT_FOR property.

[danebidev]

I see. So i guess it's a bug with UE.
I tried a bit messing around with xprop and setting it manually with no success. I guess I just won't be using fullscreen.

[orestisfl]

What you can do is create a for_window rule for this window so that once it pops up it disables fullscreen for the focused window. I can give examples later if that's not clear enough.

[danebidev]

Yeah, I thought about doing that but it's probably just not worth it. The UE spawns windows for pretty much anything. Almost any action you do opens a progress bar or dialogue popup so I would have to keep switching between fullscreen and windowed and it'd just get annoying.
Anyway, I've reported the bug to UE. Thanks for the help.

[orestisfl]

FYI we merged #6068 popup_during_fullscreen all that will allow you to see all floating windows while in fullscreen.