A "JEDIT" icon overlays the "X" icon on whatever other package is active.

[Bill Turner, wb4alm]

1. Start JEDIT
2. Start any other application.
Whatever application happens to be positioned in the left hand upper corner of the screen (i.e. second line, under the "task" bar) will have it's close icon (the "X") overlaid by a JEDIT icon, preventing you from closing the second application.

This "JE" icon background is a "light gray" with the standard orange "JE".

In the task bar, there are several other "JEDIT" icons, all colored the same - orange "JE" on a black background, one each for the internal JEDIT processes currently active.

There does not appear to be any useful function provided by this icon, as clicking on it does nothing.
- - -

I am running UBUNTU 16.04.1 with GNOME 3.20
JEDIT 5.3.0
JAVA 1.8.0_91

the following JEDIT plugins are available, but are not active (ie. "loaded")
BufferTabs 1.2.4
Character Map 1.3.3
Column Ruler 1.0.5
Common Controls 1.7.4
JDIFF Plugin 3.3.0

- - -

I also have two monitors on a single NVIDIA card. It does not matter on which screen JEDIT is started, nor does it matter if the JEDIT window is moved to the other screen. This jedit icon
is always positioned at the start of line 2 on the primary monitor, and it ALWAYS overlays the exit icon of any screen positioned there.

To close the secondary application, it is necessary to move the window down or to the right so that the "X" icon is displayed. You can then click on it to close the second application.

Clicking on this "extra" JEDIT icon does nothing...

This is NOT a misplaced JEDIT application icon for any of JEDIT's internal processes, as each of those has its own "JE" icon in the upper "task" bar, all of which properly identify themselves with a mouse-over.

- - -
<soapbox on> I am using JEDIT as my primary text editor, because GEDIT cannot be resized by grabbing one of the edges or corners, and because the work enhancing icons previously available in the now missing toolbar have been changed to menus and submenus coupled with right and left clicks and... The modifications made to GEDIT are now causing extreme slowdowns in the work that I do with my computer. <soapbox off>
- - -

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: openjdk-8-jre-headless 8u91-b14-3ubuntu1~16.04.1
ProcVersionSignature: Ubuntu 4.4.0-36.55-generic 4.4.16
Uname: Linux 4.4.0-36-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Tue Sep 13 13:49:48 2016
ExecutablePath: /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
InstallationDate: Installed on 2014-05-11 (856 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: openjdk-8
UpgradeStatus: No upgrade log present (probably fresh install)

[Bill Turner, wb4alm (wb4alm)]

Since this is never going to be looked at, and both the application and the operating system has undergone significant upgrades and changes in the past 9 years - please close this report.

[Thorsten Glaser (mirabilos)]

Closing on reporter’s request.

For what it’s worth, I cannot reproduce this with current openjdk-8 on Debian stretch with its jedit.