it is very annoying to collapse all one by one...
Collapsing and Openning recursively: Ctrl+M+L Just Collapsing: Ctrl+M+O Just Openning: Ctrl+M+P
Collapsing and Openning recursively: Ctrl+M+L
Collapsing and Openning
Just Collapsing: Ctrl+M+O
Collapsing
Just Openning: Ctrl+M+P
Openning