PgAdmin 1.2Beta crashes on ubuntu x64

Hello,

I have installed PgAdmin 1.2Beta on my computer (configuration and
versions are given below),
with ubuntu package manager (apt-get).

I have many troubles using it, PgAdmin is unstable on my computer.
I encounter several fatal crashes,
for example :
-It crashes when I want to generate an "insert script";
-It crashes when I want to add a new server;
-It crashes when I want to view the top 100 firsts rows;
etc etc ...

When PGAdmin is launched by the terminal, when it crashes, it returns :
"Segmentation fault (core dumped)"

I highly suspect something related to the GUI manager I am using, or
something related to my configuration.
What can I do ? If PGADMIN 1.2Beta remains unstable, how can I downgrad
it to a prior version ?
Many thanks in advance,

Kind regards,
Gallien LABEYRIE

--
Plateform:

gcc version 4.9.2 (Ubuntu 4.9.2-10ubuntu13)
Distribution : Ubuntu 15.04 (vivid Vervet) x64
Kernel version : 3.19.0-26-generic
CPU : Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
CPU Architecture: x86_64
Window manager : unity 7.3.2

PGADMIN version :
Version 1.200 Beta 2 (Oct 25 2014, rev:REL-1_18_0-116-gd4910ef)