idea-multimarkdown: IDE freezes when opening any markdown file

With latest version of IJ and the plugin on macos 10.13.3, the IDE is freezing more or less always (8 out of 10) when opening a markdown file while using the javafx preview mode. From the logs this might be relevant:

"AWT-EventQueue-0" prio=0 tid=0x0 nid=0x0 waiting on condition
     java.lang.Thread.State: WAITING
 on java.util.concurrent.CountDownLatch$Sync@2a4dee35
	at sun.misc.Unsafe.park(Native Method)
	at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
	at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
	at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:997)
	at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304)
	at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:231)
	at com.sun.javafx.application.PlatformImpl.runAndWait(PlatformImpl.java:337)
	at com.sun.javafx.application.PlatformImpl.runAndWait(PlatformImpl.java:307)
	at com.vladsch.idea.multimarkdown.editor.javafx.JavaFxHtmlPanel.<init>(JavaFxHtmlPanel.kt:155)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.vladsch.idea.multimarkdown.editor.javafx.JavaFxHtmlPanelProvider.createHtmlPanel(JavaFxHtmlPanelProvider.kt:87)
	at com.vladsch.idea.multimarkdown.editor.PreviewFileEditorBase$setUpPanel$1.run(PreviewFileEditorBase.kt:444)
	at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:246)
	at com.intellij.util.Alarm$Request.runSafely(Alarm.java:417)
	at com.intellij.util.Alarm$Request.access$700(Alarm.java:344)
	at com.intellij.util.Alarm$Request$1.run(Alarm.java:384)
	at com.intellij.openapi.application.TransactionGuardImpl$2.run(TransactionGuardImpl.java:315)
	at com.intellij.openapi.application.impl.LaterInvocator$FlushQueue.a(LaterInvocator.java:424)
	at com.intellij.openapi.application.impl.LaterInvocator$FlushQueue.run(LaterInvocator.java:407)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:762)
	at java.awt.EventQueue.access$500(EventQueue.java:98)
	at java.awt.EventQueue$3.run(EventQueue.java:715)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:732)
	at com.intellij.ide.IdeEventQueue.j(IdeEventQueue.java:822)
	at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:650)
	at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:366)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

When using the JB provided markdown plugin with the fx preview.