Using MX-23.2 I discovered how to restore the Greybird-mx Application and the Kokodi Window Manager (gives a blue border) themes. To duplicate the problem follow the below six steps. Don't worry about the problem I mention in my Post #7 because it is easy to restore your original themes - just remember what themes you are using (MX Tweak > Theme tab).
- In Appearance > Style tab (or MX Tweak > Theme tab > Application pane), select the Greybird-mx theme.
- In MX Tweak > Theme tab > Window Manager pane (or Window Manager > Style tab), select the Kokodi theme.
- In Appearance > Style tab, enable "Set matching Xfwm4 theme if there is one" (this option only appears in "Appearance" > Style tab).
- Now select any other theme in "Appearance" > Style tab (or MX Tweak > Theme tab > Application).
- Disable "Set matching Xfwm4 theme if there is one" (Step 3)
- Return to the Greybird-mx theme (Step 1). The issue (problem) is that the blue border that the Kokodi theme gives is no longer present.
Another strange behavior is, after Step 6 and the Kokodi theme is no longer being used, BUT the "Xfwm4 theme" is still enabled, change the Window theme to Kokodi (or if the theme still shows Kokodi as being used, select another theme and then select the Kokodi theme). You can use either MX Tweak or Window Manager to do this. Doing this will restore the Kokodi theme, HOWEVER, with the "Xfwm4 theme..." still enabled, just clicking on the already selected Greybird-mx theme will immediately go to the Greybird-mx Window theme.