Resync the project

I dont have autocomplete in monodevelop. I saw this answer : Mono Develop lost autocompletion and refactoring - Questions & Answers - Unity Discussions

but I dont know how to sync the project.
Anyone knows?

Thank you!

if the solution pad in you window was like that no problem, if it show any warning on the project name there, just click the small setting button near project name and click reload.Mostly this one happen for me.

something like this