Ubuntu 26.04/Wayland/Gtk: Resource exhaustion for message-box called in button callback

Hi,

running the test program below on Ubuntu 26.04/Wayland/Gtk4/Gnome50/Racket 9.1 and selecting "Quit", the message-box is not displayed, instead I'm getting spinning fans for a few seconds, then the program ends with "Gdk-Message: 14:15:24.255: Error flushing display: Resource temporarily unavailable" (original text for the second part in German: "Die Ressource ist zur Zeit nicht verfügbar").

The program runs just fine on Windows, both with Racket 9.0 and Racket 9.1.

I hope the information is good enough to reproduce the issue.

Thanks for the great racket/gui package :)

Best regards, Frank

#lang racket

(require racket/gui)

(define frame
  (new frame% [label "Quit example"] [width 300] [height 100]))

(define quit-button
  (new button% [parent frame] [label "Quit"]
       [callback
        (lambda (_button _event)
          (when (eq? (message-box "Quit" "Do you really want to quit?"
                                  frame '(yes-no)) 'yes)
            (send frame show #f)
            (exit 0)))]))

(send frame show #t)

Start by running the provided minimal program with racket/gui on Ubuntu 26.04, Wayland, GTK4, and GNOME 50, then compare the callback behavior with Windows. Investigate the message-box call from the button callback and the reported display-flush error. Done means the confirmation dialog appears and selecting either option exits without resource exhaustion.