Using Cuba Studio 2018.3 and Cuba Framework version 6.10.7, the data store configuration shown in CUBA > Project Properties > Data Stores does not change once Studio has started. You need to close the application and start it again for it to refresh.
This is a problem if you use Git or any other version control tool where context.xml can change when switching branches, for example, as said menu option will not reflect the actual configuration of the application.
Please update submenu content if context.xml changes.
You are using an old version of the Studio.
In order to avoid spending time investigating issues which may have been already fixed, I advise you to download latest version of the CUBA Studio (2019.1 with 11.3 plugin).
@AlexBudarov this is still applicable to CUBA Studio 2019.1.11.3: manually editing file context.xml is not reflected in CUBA > Main Data Store Settings…