Grease Pencil - Deselect strokes on ALL frames

In Edit mode, Blender has Select->None but it only deselects selected strokes on the current frame.

It would be helpful to add an option to Select None to deselect from all frames or add Deselect all frames operator in the Select menu.

Right now it is easy to just click an empty space to deselect all strokes on the current frame but there is no easy way to deselect all strokes on all frames.