previous buffer z order

By default Textadept can only switch to the previous buffer in the buffer list, not the previous buffer actually visited. In order to switch to the most recently used buffer (z-order), put the following in your ~/.textadept/init.lua:

local last_buffer = buffer
-- Save last buffer. Useful after ui.switch_buffer().
events.connect(events.BUFFER_BEFORE_SWITCH,
              function() last_buffer = buffer end)
keys[YOUR_KEY_HERE] = function()
  if _BUFFERS[last_buffer] then
    view:goto_buffer(last_buffer)
  end
end

where YOUR_KEY_HERE is your desired key binding (e.g. 'alt+l' for Alt+L.)

You can also bind a key to ui.switch_buffer(true), which lists buffers in z-order.