Since Blender 2.80 the deselect all function – complete deselection of all objects or geometry – has been switched from a single press of the “a” key to a double “a-a” or a combination of “alt+a” keycodes. To return the deselection function to a single “a” press, we can edit the settings of the selection operators. Or, since Blender 2.81, a special checkbox is provided for this in the keyboard shortcuts settings.
- Open the “Preferences” window
- Switch to the “KeyMap” section
- Turn on the “Select All Toggles” checkbox in the “Preferences” subsection
- Save the settings by pressing the “Save Preferences” button in the upper right corner of the window.
Now the selection of all objects/geometry and their total deselection will be performed by pressing the single “a” key.