Ubuntu MATE 18.04 - Yet more progress

It is all great, thank you Martin!

But I have problem with keyboard layout switching (see this post on Ubuntu Community for details).

On previous Ubuntu MATE 16.04 LTS I can use Ctrl+Shift shortcut for keyboard layout switching without problems, but on 16.04 LTS with HWE, 17.10 and 18.04 LTS I can't.

Quote from bug 1720364 is below:

Steps to reproduce:

  1. Install ubuntu-mate-desktop on Ubuntu 16.04 LTS with HWE, or 17.10 or 18.04 LTS..
  2. Set-up two keyboard layouts - English and Russian
  3. Set Ctrl+Shift as keyboard layout switcher
  4. Try to use shortcuts starting from Ctrl+Shift:
    4.1. Open Firefox, open new tab, go to some site in it, close tab, try to click Ctrl+Shift+T to restore closed tab.
    4.2. Open mate-terminal, try to open new tab with Ctrl+Shift+T, or copy (Ctrl+Shift+C), or paste (Ctrl+Shift+V).
    4.3. Open pluma, write some text, try to navigate in it with Ctrl+Shift+arrow.

Expected results:
Ctrl+Shift switches keyboard layout, shortcuts starting from Ctrl+Shift+... work normally.

Actual results:
Ctrl+Shift switches keyboard layout, shortcuts starting from Ctrl+Shift+... do not work.

Is it possible to fix this problem before official 18.04 LTS release?