Choose in Menu, Service Contracts, tab more information, and add a ticket.
This ticket not maintain relation with the service contract.
If you try the same way, fot create a new to do, will not able to set a contracts service in relation field and will need to put a contact manually, too.
Yes, you have to fill in the fields manually, but the records are correctly related on save.
It is impossible to establish all the relations and capture fields in the system, not only are there too many but also you can create as many as you need. If you need to fill in some fields automatically that functionality has to be added specifically for your use case.
But in another parts of system, when I do the same, system complete this fields, for example if you active Account module, system will complete relation to field.
And, if you try created a new todo, from menu, not is possible choose relation to service contracts
As I said above, it is impossible to foresee and prepare all the different possible combinations anyone can construct. Some have been implemented, others have not. If you need one you can add it. You can even share it with the project too :-)
I'm not quite sure what you want to do. If you want to add Service Contracts to the calendar related field and then you will need a cbupdater update with some vtlib code to capture the field and add the relation. That is in case you want to share it with everyone. If you just want to add it to your install a simple vtlib script can do that easily or directly insert into vtiger_fieldmodulerel
If you want to fill in other fields, the field mapping business map should be able to do that or you can add some code to the EditView.php script in calendar like you will find in Payments, or many inventory modules.
find the fieldid of those two fields, go to the vtiger_fieldmodulerel table and look for those fieldid and add another record for the module you want to support
