Cannot assign platforms to test plan

[emds73]

Testlink version: 1.9.20-1
Installer: Windows 64 bit
S.O. : Windows 10
Have you installed any plugin or modified any configuration file? : NO

Issue:
When I select the "Add/Remove Platform" option, "Avaible platforms" and "Assigned platforms" lists are empty., and it's impossible assign platforms.

Steps:
1) Create test plan
2) Create two platforms: Android and Windows, with "On desing" and "On execution" options checked
3) Select the test plan, and click "Add/Remove platforms" - "Avaible platforms" and "Assigned platforms" lists are empty.
4) Add build to test plan
5) Add test suite to test plan
6) Try again "Add/remove platform" - "Avaible platforms" and "Assigned platforms" lists are empty.

What's wrong?

[fman]

If you need to report issues the right place is mantis.testlink.org
PLease get github branch test link_1_9_20_fixed and use it because several 1.9.20 issues have been fixed.
Give a look in mantis.testlink.org for solved issues