Commands in this menu allow to select vector objects with use of various criteria, or modify existing selection.
The first command is Zoom to Selected Objects. This command scrolls selected object(s) to center of the screen and zooms in or out to fit selection to the screen. It helps to localize object(s) selected in the Inspector window in the work area.
Next command Zoom and Edit Selected Objects works in the same way as above command, but it also starts nodes editing mode.
New Selection, Add to Selection and Select Subset options allow to define the way of how vector objects are selected.
Rest of the commands in this menu allows to select multiple objects of the same type (like Roads, POIs with address) at once. They work with either whole map or just selection, according to selection mode defined by above options.