ADDITIONAL SYSTEM INFORMATION :
Darwin unit 17.6.0 Darwin Kernel Version 17.6.0: Tue May 8 15:22:16 PDT 2018; root:xnu-4570.61.1~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
The test fails on MacOS with the message
"JDesktopPane isn't transparent. Expected color is (red color): java.awt.Color[r=255,g=0,b=0], actual color is: java.awt.Color[r=251,g=0,b=7]"
The issue was also observed on Windows and never been observed on Linux.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
$ jtreg -ignore:quiet -v -a -xml -compilejdk:"/Library/Java/JavaVirtualMachines/jdk-10.0.1.jdk/Contents/Home" -testjdk:"/Library/Java/JavaVirtualMachines/jdk-10.0.1.jdk/Contents/Home" -javaoptions:"-Djava.awt.headless=false" test/javax/swing/JInternalFrame/5066752/bug5066752.java

ACTUAL -
#section:main
----------messages:(5/181)----------
command: main bug5066752
reason: User specified action: run main bug5066752
Mode: othervm
Additional options from @modules: --add-modules java.desktop
elapsed time (seconds): 4.41
----------configuration:(3/40)----------
Boot Layer
  add modules: java.desktop

----------System.out:(0/0)----------
----------System.err:(14/1246)----------
WARNING: GL pipe is running in software mode (Renderer ID=0x1020400)
java.lang.Exception: Test failed: JDesktopPane isn't transparent. Expected color is (red color): java.awt.Color[r=255,g=0,b=0], actual color is: java.awt.Color[r=67,g=67,b=67]
at bug5066752.main(bug5066752.java:55)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:115)
at java.base/java.lang.Thread.run(Thread.java:844)

JavaTest Message: Test threw exception: java.lang.Exception: Test failed: JDesktopPane isn't transparent. Expected color is (red color): java.awt.Color[r=255,g=0,b=0], actual color is: java.awt.Color[r=67,g=67,b=67]
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.Exception: Test failed: JDesktopPane isn't transparent. Expected color is (red color): java.awt.Color[r=255,g=0,b=0], actual color is: java.awt.Color[r=67,g=67,b=67]


---------- BEGIN SOURCE ----------
http://hg.openjdk.java.net/jdk9/jdk9/jdk/file/65464a307408/test/javax/swing/JInternalFrame/5066752/bug5066752.java
---------- END SOURCE ----------

FREQUENCY : always