I am working with Symfony. Every time I use \"ctrl+shift+n\" to go to a file, PhpStorm is looking into every vendors to try to find the file and thus spoils the
Your only option right now is to do what you did -- exclude folders from vendors directory. You just need to do it a bit differently -- you still need to reference it back...
vendors/symfony)Settings (Preferences on Mac) | Languages & Frameworks | PHP)In theory -- excluding whole vendor folder and then adding it back via Include Paths will also work .. but I prefer having a bit better control and do it on individual packages/vendors level.
Plus, the Composer integration does basically the same (if such option is enabled) but will do it on actual package level (vendors/symfony/symfony) instead of proposed here upper vendor level (vendors/symfony).
After you do this you will see results from such excluded folders ONLY if there will be no matches in actual project files... or if you enable inclusion of non-project matches.
If you are using Composer ... just enabling that option should be enough (you need to provide path top your composer.json for that, of course)



UPDATE 2020-08-15: Since 2020.1 or so you can use Scopes in Ctrl + Shift + N popup and alike (Search Everywhere, navigate to File/Class/Symbol/etc).
P.S. It may not be remembered between IDE sessions (there are tickets about that) but definitely remembered in the same session.