unwanted space character in gnuplot auto complete

[Guido]

I made a fresh install of Ubuntu 14.04. Then I installed gnuplot, version 4.6 patch 4. When I use the autocomplete features, it always adds a space after the correctly completed name. If the filename is foo.txt, the autocomplete feature will fill in "foo.txt ", which does not allow to use the file. This is extremely annoying, as you need to delete the additional space by hand every time. I found no other indication (nor solutions) of such a bug, except for
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=743014#5

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: gnuplot 4.6.4-2
Uname: Linux 3.17.0-031700-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Feb 17 19:01:24 2015
Dependencies:

InstallationDate: Installed on 2015-01-13 (35 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
PackageArchitecture: all
SourcePackage: gnuplot
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[M Rahman (remon-pp)]

facing same bug here on

Gnuplot 4.6 Patchlevel 6

Ubuntu 15.04