"sync the project with gradle files" button disappear

One day I found my "sync the project with gradle files" button disappear when I update to Android Studio 1.5...

This is a very terrible thing because I don't know what's going on !!?

I search a lot of infomations about that.

Finally ....

I found a solution that

1. Open Gradle tool window with [View] -> [Tool Windows] -> [Gradle]
2. Start Macro Recording with Edit -> Macros -> Start Recording Macro
3. In Gradle tool window press Refresh all Gradle projects button
4. Stop Macro Recording with Edit -> Macros -> Stop Recording Macro
5. Save Macro with name Gradle sync

Ref stackoverflow