There is a Navigation View Controller, from which the segue goes to the Table View Controller 
There are two custom cells in the Table View Controller. From each button (i) go show segue to the controller view. Its contents do not matter. Although it is, although it is not.
Also, from the Master View Controller is segue on the Tab View Controller.
So here. At startup, it looks like this:
By clicking on the cell, the code editor opens, as intended.
But for reasons unknown to me, by clicking on any of the buttons (i) (Although it doesn’t matter which button to press, like it is the same Prototype Cell, and when called, they perform the same segue) this...
Spent a few days on this. Help who understands. I will be very grateful.
UPD: I rewrote the application a bit. Now the detail-button is a standard accessory, by clicking on which the function performSegue is called. It finally worked, but only on the iOS 9.2 simulator. On iOS 10.2 on a real machine, it still crashes ... I completely ceased to understand what is happening ...
