To reproduce:

1. Run the attached test case:
$ java --module-path javafx-sdk-13/lib --add-modules javafx.controls HelloSimple

2. Press the "Platform.exit" button

3. BUG: The program will exit, but prints the following assertion error:

Java has been detached already, but someone is still trying to use it at -[GlassViewDelegate dealloc]:/Users/jenkins/workspace/OpenJFX-mac/modules/javafx.graphics/src/main/native-glass/mac/GlassViewDelegate.m:198
0 libglass.dylib 0x0000000128ba8f92 -[GlassViewDelegate dealloc] + 290
1 libglass.dylib 0x0000000128baec9c -[GlassView3D dealloc] + 252
2 libobjc.A.dylib 0x00007fff75e4953a _ZN19AutoreleasePoolPage12releaseUntilEPP11objc_object + 134
3 libobjc.A.dylib 0x00007fff75e2fc30 objc_autoreleasePoolPop + 175
4 CoreFoundation 0x00007fff48b144be __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
5 CoreFoundation 0x00007fff48b143e4 __CFRunLoopDoObservers + 457
6 CoreFoundation 0x00007fff48ab755b __CFRunLoopRun + 1219
7 CoreFoundation 0x00007fff48ab6e13 CFRunLoopRunSpecific + 499
8 libjli.dylib 0x0000000105bff619 CreateExecutionEnvironment + 399
9 libjli.dylib 0x0000000105bfb75e JLI_Launch + 1354
10 java 0x0000000105bf0ca9 main + 367
11 libdyld.dylib 0x00007fff7718b405 start + 1