I found an alternative solution.
There is a Slingshot Launcher fork call Panther Launcher. It looks and works exactly the same.
It is faster and it does not depend on Gala or Granite.
Download the Ubuntu 64 bit version and install it.
Then open System Settings - Desktop - Hot Corners
Select the top left corner and choose Execute Custom Command and set it to
Then go back to System Settings - Keyboard - Custom and add a new shortcut.
The first time you launch Panther might freeze but try again and it will work just fine after.
If you want to customize the amount of columns, icon size, etc. Open Dconf-editor and go to
Once you finish customizing you need to kill Panthern and launch it again.
So far this is the best solution for me, I don't know why but Slingshot it is very laggy and I would love to use it by default.