The test com/sun/java/swing/plaf/gtk/bug6492108.java intermittently fails on Ubuntu 20.04, Ubuntu 22.04 as follows:

-----------------------------8<=============================
#section:main
----------messages:(7/290)----------
command: main bug6492108
reason: User specified action: run main/othervm bug6492108
started: Thu Jun 13 07:37:10 NOVT 2024
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.desktop
finished: Thu Jun 13 07:37:11 NOVT 2024
elapsed time (seconds): 0.787
----------configuration:(3/40)----------
Boot Layer
  add modules: java.desktop

----------System.out:(2/36)----------
invoking: onEDT10
invoking: onEDT20
----------System.err:(25/1835)----------
java.lang.RuntimeException: Image comparison failed for images at index 0 and 4
at SwingTestHelper.fail(SwingTestHelper.java:720)
at bug6492108.onEDT20(bug6492108.java:141)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at SwingTestHelper.invoke(SwingTestHelper.java:654)
at SwingTestHelper$6.run(SwingTestHelper.java:638)
at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:308)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:773)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:720)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:714)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:400)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

JavaTest Message: Test threw exception: java.lang.RuntimeException: Image comparison failed for images at index 0 and 4
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: Image comparison failed for images at index 0 and 4
-----------------------------8<=============================

The failure was reproducible on x86-64, aarch64.
The issue was observed on jdk23, jdk24
Note: refImg.png cannot be opened after test execution - Image Viewer returns the error: "Fatal error reading PNG image file: PNG unsigned integer out of range"

The following change adding a short delay at the end of creating content pane resolves this issue

        try {
            addTextComps(panel, JTextArea.class);
            addTextComps(panel, JEditorPane.class);
            addTextComps(panel, JTextPane.class);
         } catch (Throwable t) {
             fail("Problem creating text components");
         }
+ setDelay(50);
         return panel;
     }