I was testing NetBeans on the latest build of lanai, which includes the fix for JDK-8261703.

I ran NetBeans in dual screen mode with the following env variables set:

_JAVA_OPTIONS="-Dsun.java2d.metal=True"
MTL_SHADER_VALIDATION=1
METAL_DEVICE_WRAPPER_TYPE=1

I dragged NB between the two screen with no problems.

Then I did some playing around with it where I expanded various libraries in the Navigation panel, eventually, it crashed with this assertion, but I have been unable to reproduce it:

-[MTLDebugRenderCommandEncoder validateFramebufferWithRenderPipelineState:]:1257: failed assertion `For stencil attachment, the render pipeline's pixelFormat (MTLPixelFormatInvalid) does not match the framebuffer's pixelFormat (MTLPixelFormatStencil8).'

/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform/lib/nbexec: line 425: 30541 Abort trap: 6 "/Users/kcr/dev/java/lanai-clean/build/macosx-x64/images/jdk/bin/java" -Djdk.home="/Users/kcr/dev/java/lanai-clean/build/macosx-x64/images/jdk" -classpath "/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform/lib/boot.jar:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform/lib/org-openide-modules.jar:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform/lib/org-openide-util-lookup.jar:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform/lib/org-openide-util-ui.jar:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform/lib/org-openide-util.jar" -Dnetbeans.default_userdir_root="/Users/kcr/Library/Application Support/NetBeans" -Dnetbeans.dirs="/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/nb:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/ergonomics:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/ide:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/extide:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/java:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/apisupport:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/webcommon:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/websvccommon:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/enterprise:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/mobility:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/profiler:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/python:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/php:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/identity:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/harness:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/cnd:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/cndext:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/dlight:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/groovy:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/extra:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/javacard:/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/javafx:" -Dnetbeans.home="/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/platform" '-Xdock:name=NetBeans' '-Xdock:icon=/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/nb/netbeans.icns' '-Dnetbeans.importclass=org.netbeans.upgrade.AutoUpgrade' '-XX:+UseStringDeduplication' '-Xss2m' '-Djdk.gtk.version=2.2' '-Dapple.laf.useScreenMenuBar=true' '-Dapple.awt.graphics.UseQuartz=true' '-Dsun.java2d.noddraw=true' '-Dsun.java2d.dpiaware=true' '-Dsun.zip.disableMemoryMapping=true' '-Dplugin.manager.check.updates=false' '-Dnetbeans.extbrowser.manual_chrome_plugin_install=yes' '--add-opens=java.base/java.net=ALL-UNNAMED' '--add-opens=java.base/java.lang.ref=ALL-UNNAMED' '--add-opens=java.base/java.lang=ALL-UNNAMED' '--add-opens=java.base/java.security=ALL-UNNAMED' '--add-opens=java.base/java.util=ALL-UNNAMED' '--add-opens=java.desktop/javax.swing.plaf.basic=ALL-UNNAMED' '--add-opens=java.desktop/javax.swing.text=ALL-UNNAMED' '--add-opens=java.desktop/javax.swing=ALL-UNNAMED' '--add-opens=java.desktop/java.awt=ALL-UNNAMED' '--add-opens=java.desktop/java.awt.event=ALL-UNNAMED' '--add-opens=java.prefs/java.util.prefs=ALL-UNNAMED' '--add-opens=jdk.jshell/jdk.jshell=ALL-UNNAMED' '--add-modules=jdk.jshell' '--add-exports=java.desktop/sun.awt=ALL-UNNAMED' '--add-exports=java.desktop/java.awt.peer=ALL-UNNAMED' '--add-exports=java.desktop/com.sun.beans.editors=ALL-UNNAMED' '--add-exports=java.desktop/sun.swing=ALL-UNNAMED' '--add-exports=java.desktop/sun.awt.im=ALL-UNNAMED' '--add-exports=jdk.internal.jvmstat/sun.jvmstat.monitor=ALL-UNNAMED' '--add-exports=java.management/sun.management=ALL-UNNAMED' '--add-exports=java.base/sun.reflect.annotation=ALL-UNNAMED' '-XX:+IgnoreUnrecognizedVMOptions' -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath="/Users/kcr/Library/Application Support/NetBeans/12.0/var/log/heapdump.hprof" org.netbeans.Main --cachedir "/Users/kcr/Library/Caches/NetBeans/12.0" --userdir "/Users/kcr/Library/Application Support/NetBeans/12.0" "--branding" "nb" 0<&0