如何为Goland中的现有项目索引整个GOPATH？

When I create a project, I forgot to check [index entire GOPATH]. So currently, the project can't find third party modules.

Even though I checked [index entire GOPATH] option for this project in Preferences | Go | GOPATH | Project GOPATH, the project doesn't index the entire GOPATH.

Edit:

I deleted .idea directory and opened the project again, it works fine now.