Enable undo in textboxes

[kyoshino]

Undo (Ctrl-Z) in textboxes doesn't work when:

• Adding UA info or extension list into a textbox
• Editing custom title template in the extension options

From #245 (comment):

The Paste event might be the solution, but it's not supported in the content script yet. I also tried document.execCommand('insertText', false, str) with no luck.

[akshat14714]

@kyoshino I am a newbie, and I want to solve this issue. Can you help me in solving this?

[kyoshino]

I'm also a newbie actually 😄 Please give it a shot if you can.

[MikkCZ]

If the API is not supported, I suggest to use the standard history API (I guess this is supported) to store the previous textbox state and listen to Ctrl+Z/Ctrl+Shift+Z/Ctrl+Y key presses. Or we can store the input history in memory, but that has a potential to leaks.

[kyoshino]

The Undo Manager API has already been removed from Firefox 😿

[xabolcs]

WebExtension Experiments could help here? If yes, then it could be done as a separate issue / workaround for Nightly and Developer Edition to not forget about Firefox Beta / Release and other Gecko (SeaMonkey, Thunderbird?) users.