AUI2 is based on wx.lib.agw.aui, with some bug fixes and improvements

1. fix issue 2348
2. fix issue 2356
3. fix issue 2359
4. fix issue 2361
5. fix issue 2362
6. fix issue 2364
7. improve dark mode
   1. not work for notebook chrome theme and docking guide, as they are bitmap based.
   2. not work on windows
8. issue 2374
9. integrate with auibarpopup

1. Install

$ pip install aui2

2. Import aui2

import aui2 as aui