Text editor is not working in Firefox 78?

[david (David Taylor)]

@Falco

You need to update to the current ESR version (102) or at least the previous one (91)

I just double checked via BrowserStack, and the toolbar formatting buttons work correctly under Firefox 91

@sam

My guess here @david is that this may be related to the undo support?

Yeah, via MDN, Firefox < 89 had bugs with text manipulation:

Before Firefox 89, manipulating the content of <input> and <textarea> elements using Document.execCommand() commands requires workarounds (see bug 1220696).