How's the "Jira Project" field in the release vehicle populated?

[Gyanendra_gupta]

I have a few Release vehicles (RV) for a Program and one of the RV has the  "Jira Project" grayed with the Jira Project is filled in.  Some other RVs  are grayed, with "Jira Project No Sync".  And I can not add the Jira Project to it.  

I am wondering how does the "Jira Project" field get populated and how can I force data in this field.

Thanks in advance for your wisdom.

ADDITIONAL INFORMATION:

Why is the Jira Project field drop down unavailable in certain cases, it's already filled and can not be changed, and in some cases it is filled but can be updated from a drop down.

What drives it?

We have program identified and all teams are connected in Settings.  

HELP!!

[Shannon Wright]

The RV with a current Jira Project name listed are ones that have synced with Jira.  If your connector settings are configured with the setting to allow RV(fixed versions) to sync, then that information will sync.

• Allow Release Vehicles to sync with Jira Fix Versions. Select Yes to allow Jira fix versions to synchronize with Jira Align. If this option is turned off, fix versions do not synchronize. 
  
  

The ones listed in Align with "no sync" next to Jira project simply means that the information is not configured to an existing Jira project.  In my instance, I have the ability to click on the dropdown and select a jira project I want the RV to sync down to.  This will be dependent on if the Program Increment includes programs that have jira projects already configured to sync.

[Gyanendra_gupta]

Thank you. Configuration is correct but it's still not working for all RVs.  

[Gyanendra_gupta]

Please see my updates to the original question. Thanks.