Hello again Saif
Yes of course forgot to mention that, set all the surfaces that are affected by the changes you make in the corridor to ”By user” (I noticed that the rebuild automatic in your project is a time killer).
When put the surfaces in the ”By user” mode you will have to choose the surface in the Project explorer, right click and choose rebuild when you are done and satisfied with your changes. You can also put them back to rebuild automatic whenever you like.
All the subgrades/materials that you create in the corridor (in this case you have only one) won’t be created automatically, to create a corridor surface go to the corridor ribbon and choose the command ”Corridor surface”.
Cheers mate