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 > >
