Alt + Ctrl + [(Mac: ⌥⌘ [)): Folds the code when the current cursor is the starting point of a scope. (a line with a shape on the left)
Alt + Ctrl +] (Mac: ⌥⌘])): Unfolds the collapsed area. This does not work at the end of the collapsed area.
Ctrl + K + 1 (Mac: ⌘K1)): Folds all unfolded areas.
Ctrl + K + 0 (Mac: ⌘K0)): Unfolds all collapsed areas.