Eclipse crashes while opening template

[qtdzz]

Steps to reproduce

1. Run Eclipse 2018-12 in Ubuntu 18.04
2. Open a flow template

Actual behavior

the Eclipse crashes with the log

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007f5b4c0f485c, pid=23452, tid=0x00007f5c56973700
#
# JRE version: Java(TM) SE Runtime Environment (8.0_201-b09) (build 1.8.0_201-b09)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.201-b09 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# C  [libgdk-x11-2.0.so.0+0x4e85c]  gdk_display_open+0x5c
#

Expected behavior

It should works

IDE, Designer and OS version

Eclipse 2018-12, Designer 4.2.1, Ubuntu 18.04 with JDK8 < 1.8.0_202

Information

Since Eclipse 2018-12 (4.10.0), support for GTK2 has been dropped and the current e(fx)clipse in Designer doesn't support GTK3 for JDK8 < 1.8.0_202. So it causes the crash.
To fix this issue, we need

• Update e(fx)clipse to 3.5.0 (related issue Allow GTK3 with JDK8u202+ eclipse-efx/efxclipse-rt#291)
• Recommend users to use JDK8 >= 1.8.0_202 which contains GTK3 support.
• Remove GTK3 warning box if user is using GTK3 + Eclipse >=4.10.0 + JDK8 >= 1.8.0_202