Would there be any way to guard against the bug from the JavaFX-side so
that an invisible popup won't be shown when it happens? Doesn't have to
be pretty, just to avoid the most glaring issue
On 16/08/2026 02:56, Thiago Milczarek Sayão wrote:
Hi,
It seems that this is a bug in Mutter.
I tried disabling frame synchronization using
gdk_x11_window_set_frame_sync_enabled(), but the issue still occurs.
I also tried forcing an Expose event after the popup was mapped, but that
did not solve the problem either.
The popup window is mapped correctly, but occasionally it is not rendered
on screen.
See (the video shows one run, but i did many with the same result):
youtube.com/watch?v=1LB2OLrYex8&feature=youtu.be
Xephyr :100
DISPLAY=:100 java @/home/tsayao/jfx/build/run.args AutoPopupTest.java
Test 1:
No window manager - bug does not happen
Test 2:
kwin - bug does not happen
DISPLAY=:100 dbus-run-session kwin_x11 --replace
Test 3:
mutter - bug happens
DISPLAY=:100 dbus-run-session -- mutter --x11
-- Thiago.
Em ter., 11 de ago. de 2026 às 20:18, Martin Fox <[email protected]>
escreveu:
For those of you who haven’t looked at the bug report, it has to do with
GDK expecting the windowing system to send it a _NET_WM_FRAME_DRAWN message
but the message never arrives. If this is something you have any experience
with feel free to jump in and investigate (because I’m at a loss).
It looks like we’re not the only one seeing this. I ran across a thread
detailing how GVim sometimes freezes (vim/vim repository on GitHub, issue
#12671) and they also concluded it was due to GDK not receiving this
message. The Discourse discussion contains more information (link in the
JBS ticket). They were not able to resolve the problem.
Martin
On Aug 10, 2026, at 11:59 AM, Andy Goryachev <[email protected]>
wrote:
I think this scenario warrants bumping the issue to P3.
-andy
From: PavelTurk <[email protected]>
Date: Sunday, August 9, 2026 at 23:55
To: [email protected] <[email protected]>
Subject: [External] : Using JavaFX on Linux can be dangerous
Hi everyone,
I would like to warn everyone and provide some feedback regarding the
use of JavaFX on Linux. We developed a small application and gave it to
a small number of the customer’s employees for testing. The application
was tested on both Linux and Windows.
We encountered serious problems on Linux. Due to bug JDK-8371781, popup
windows are not displayed to the user, but they are still present in the
scene. As a result, a user can click on elements in these popups without
being able to see them, potentially triggering actions that they
absolutely should not be able to perform.
Therefore, I decided to bring this issue to the attention of the JavaFX
developers and warn others about the potential safety implications of
using JavaFX on Linux.
Best regards, Pavel
