Fixing Ctrl + Z for editor toolbar button actions in non-Firefox browsers

[Sujan (Jan P.)]

See the previous discussion I linked to:

Undo (Ctrl/Cmd+Z) doesn't work for Markdown

You can’t undo (Ctrl/Cmd+Z) Markdown formatting (e.g., bold). Steps to replicate: Start a new topic. Write three words. Highlight the second word and press Ctrl/Cmd+B Press Ctrl/Cmd+Z Expected result: Asterisks would be removed Actual result: Different in different browsers tested (Safari & Chrome on macOS), but not the expected result.

(Note: It works as expected in Firefox, but not most other browsers)