BUG #12912: pgAdmin III : set fonts preferences makes pgAdmin to crash

The following bug has been logged on the website:

Bug reference:      12912
Logged by:          Thomas Williamson
Email address:      wiltoma@gmail.com
PostgreSQL version: 9.4.1
Operating system:   OS X Yosemite 10.10.1
Description:

Here is how the bug occurs:

1. Launch pgAdminIII 1.20
2. Go to 'Preferences'
3. Go to first menu 'Navigateur' (in french)
4. Go to fourth menu 'Divers interface' (in french)
5. Click on 'fonts' button (large button at the top)
6. Select either a font or a font size
7. pgAdmin crashes!

I tried to install pgAdminIII 1.18 and 1.16: same issue.

Here is what a SELECT version(); reports:

"PostgreSQL 9.4.1 on x86_64-apple-darwin, compiled by
i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build
5658) (LLVM build 2336.11.00), 64-bit"

Thanks for help...