can't go fullscreen with picture-in-picture mode (firefox)

cvcarloscv · 2026-08-30 14:17:46

i'm using arch linux with xfce (x11 with default compositor and WM.) system is updated to this date.

firefox works and i can go fullscreen when using the browser normally. i can't go fullscreen in PiP mode though: the pop-up video player's HUD freezes when i click the fullscreen icon or press F. no fullscreen, video keeps playing though. also i can use the HUD for pausing, volume, etc, its just stuck. closing PiP and starting it again fixes the HUD.

i have no idea how to debug this, and i really want the fullscreen option to work. it used to work on debian 13 before, but not on arch. what do i do?

video showcasing the problem

CPU: AMD Ryzen 5 3500C (8) @ 2.10

GPU: AMD Radeon Vega 8 Graphics [Integrated]

seth · 2026-08-30 15:26:43

Sure you're not trying to use https://wiki.archlinux.org/title/Xfce#U … nd_support ?
Does it work as expected in an openbox session?

cvcarloscv · 2026-08-30 18:42:53

seth wrote:

Sure you're not trying to use https://wiki.archlinux.org/title/Xfce#U … nd_support ?

nope! 100% sure i'm using x11. here's the full output from fastfetch:

                  -`                     cv@arch-ezkinil
                 .o+`                    ---------------
                `ooo/                    OS: Arch Linux x86_64
               `+oooo:                   Host: Ezkinil (rev4)
              `+oooooo:                  Kernel: Linux 7.1.11-zen1-1-zen
              -+oooooo+:                 Uptime: 7 hours, 8 mins
            `/:-:++oooo+:                Packages: 1401 (pacman)
           `/++++/+++++++:               Shell: zsh 5.9.2
          `/++++++++++++++:              Display (AUO403D): 1920x1080 in 14", 60 Hz
         `/+++ooooooooooooo/`            DE: Xfce4 4.20
        ./ooosssso++osssssso+`           WM: Xfwm4 (X11)
       .oossssso-````/ossssss+`          WM Theme: Redmond97 SE Jet Purple
      -osssssso.      :ssssssso.         Theme: Redmond97 SE Jet Purple [GTK2/3/4]
     :osssssss/        osssso+++.        Icons: SE98 [GTK2/3/4]
    /ossssssss/        +ssssooo/-        Font: Tahoma (10pt) [GTK2/3/4]
  `/ossssso+/:-        -:/+osssso+-      Cursor: Chicago95_Standard_Cursors_Black (16px)
 `+sso+:-`                 `.-/+oso:     Terminal: xfce4-terminal 1.2.0
`++:.                           `-/+/    Terminal Font: Less Perfect DOS VGA (12pt)
.`                                 `/    CPU: AMD Ryzen 5 3500C (8) @ 2.10 GHz
                                         GPU: AMD Radeon Vega 8 Graphics [Integrated]
                                         Memory: 3.10 GiB / 7.21 GiB (43%)
                                         Swap: 1.43 GiB / 12.00 GiB (12%)
                                         Disk (/): 200.19 GiB / 462.65 GiB (43%) - btrfs
                                         Battery (AP19B8M): 99% [AC Connected]
                                         Locale: C.UTF-8

seth wrote:

Does it work as expected in an openbox session?

it doesn't work! same thing in the video happens. weirdly enough, i tried in iceWM just to test a different enviroment and PiP does work in there. what could be happening?

seth · 2026-08-30 19:59:49

I don't think IceWM is NETWM compatible - what's the output of "xprop" for both windows (browser an video) when this happens?
(The cursor will turn into a "+", you can click a window and it will print a lot of text on the console)

What WM did you use on Debian?
XFWM4 as well?

cvcarloscv · Yesterday 21:33:45

seth wrote:

what's the output of "xprop" for both windows (browser an video) when this happens?

xprop output on pastebin. i did the command after PiP fullscreen button was clicked and UI got frozen. (done on xfwm4, did you mean i should do it on icewm?)

seth wrote:

What WM did you use on Debian?

KDE default (kwin), also on x11

killertofus · Yesterday 23:27:46

does wayland work?

seth · Today 05:43:58

WM_STATE(WM_STATE):
		window state: Normal
_NET_WM_STATE(ATOM) = _NET_WM_STATE_SKIP_PAGER, _NET_WM_STATE_SKIP_TASKBAR, _NET_WM_STATE_ABOVE
		Initial state is Normal State.

None of those windows is set to fullscreen (the above one is the PiP one)

_NET_FRAME_EXTENTS(CARDINAL) = 0, 0, 0, 0

Does it work if you run

killall firefox; MOZ_GTK_TITLEBAR_DECORATION=system firefox

cvcarloscv · Today 13:12:49

killertofus wrote:

does wayland work?

yes. ran a xfce wayland session with labwc as the compositor and it did work. the problem seems to be WM related then

seth wrote:

Does it work if you run

killall firefox; MOZ_GTK_TITLEBAR_DECORATION=system firefox

nope, same issue as before. the windows decorations do change for the main firefox window, but PiP window looks exactly the same and has the exact same bug (UI freezes, fullscreen doesn't work)

Arch Linux

#1 2026-08-30 14:17:46

can't go fullscreen with picture-in-picture mode (firefox)

#2 2026-08-30 15:26:43

Re: can't go fullscreen with picture-in-picture mode (firefox)

#3 2026-08-30 18:42:53

Re: can't go fullscreen with picture-in-picture mode (firefox)

#4 2026-08-30 19:59:49

Re: can't go fullscreen with picture-in-picture mode (firefox)

#5 Yesterday 21:33:45

Re: can't go fullscreen with picture-in-picture mode (firefox)

#6 Yesterday 23:27:46

Re: can't go fullscreen with picture-in-picture mode (firefox)

#7 Today 05:43:58

Re: can't go fullscreen with picture-in-picture mode (firefox)

#8 Today 13:12:49

Re: can't go fullscreen with picture-in-picture mode (firefox)

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