ADDITIONAL SYSTEM INFORMATION :
CentOS Linux release 7.5.1804 (Core)
jmc-7-ea+05_linux-x64_bin (openjdk version "11.0.1" 2018-10-16)

A DESCRIPTION OF THE PROBLEM :
JMC randomly crashes after some usage mentioning libjavascriptcoregtk-4.0.

N.B.: Other eclipse/swt-based products (Eclipse Photon, Eclipse Oxygen, SmartGit) using versions of OpenJDK 1.8 and Oracle JDK 1.8 work fine. I did not try running any of these products on JDK 11-ea.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start JMC from the commandline and start using it.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
JMC should not just crash.
ACTUAL -
After a short time JMC will crash mentioning libjavascriptcoregtk:

1. jmc/bin/jmc
   Started recording 1.

Use jcmd 18726 JFR.dump name=JMC_Default filename=FILEPATH to copy recording data to file.

(JDK Mission Control:18726): Gtk-WARNING **: gtk_widget_size_allocate(): attempt to allocate widget with width -3 and height 1

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar

(JDK Mission Control:18726): Gtk-CRITICAL **: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkScrollbar
#

1. A fatal error has been detected by the Java Runtime Environment:
   #
2. SIGSEGV (0xb) at pc=0x00007f7f903d2cd2, pid=18726, tid=19001
   #
3. JRE version: OpenJDK Runtime Environment (11.0.1+9) (build 11.0.1+9)
4. Java VM: OpenJDK 64-Bit Server VM (11.0.1+9, mixed mode, tiered, compressed oops, g1 gc, linux-amd64)
5. Problematic frame:
6. C [libjavascriptcoregtk-4.0.so.18+0x90fcd2]
   #
7. Core dump will be written. Default location: Core dumps may be processed with "/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t e %P %I %h" (or dumping to /home/rene/.local/core.18726)
   #
8. An error report file with more information is saved as:
9. /home/rene/.local/hs_err_pid18726.log
   #
10. If you would like to submit a bug report, please visit:
11. http://bugreport.java.com/bugreport/crash.jsp
    #