For Mac OS X users YASQE shows a hint that the keyboard shortcut to trigger autocompletion is Cmd+space. However, this invokes the default system tool Spotlight. Since Ctrl+space triggers the autocompletion and Cmd+space (probably) cannot be overridden, the hint for the keyboard shortcut can be the same across all OSs; i.e. Ctrl+space.
For Mac OS X users YASQE shows a hint that the keyboard shortcut to trigger autocompletion is Cmd+space. However, this invokes the default system tool Spotlight. Since Ctrl+space triggers the autocompletion and Cmd+space (probably) cannot be overridden, the hint for the keyboard shortcut can be the same across all OSs; i.e. Ctrl+space.