How to return the familiar selection mode from Blender 2.7 in Blender 2.8

In Blender 2.8 the selection mode has been changed. The “select all” command is still mapped to pressing the “a” key, but the “deselect all” command in Blender 2.8 is now mapped to a double-click of the “a” key or to the “alt + a” key combination. However, it is easy to return the familiar selection mode from Blender 2.7 – selecting and deselecting all by pressing one “a” key.

To do this, in the “Preferences” window in the “Keymap” section type “object.select” in the search field. In the search results in the “Object mode” section in the line with “a” key snapping set the “Toggle” value to the “Action” parameter.

This will return the familiar selection in object mode.