I use Edge on Win11. Very occasionally text selection and typing simply quits working in the browser and only the browser. Usually after I’ve opened and closed a couple hundred tabs since the last time the browser was restarted. Since a large fraction of my browsing & tabs are here, it usually manifests at the Dope. But I don’t think it’s caused by the Dope.
Anyhow closing all the browser(s) you may have open then starting a fresh browser instance solves the problem with 100% reliability for me.
As a separate matter to the above …
There are reports that the [quote] pop-up sometimes does not appear when text is selected. I’ve seem it myself. Seems to be a random glitch, but it does sometimes happen almost regardless of device, OS, or browser. Suggesting a Discourse glitch. IME if the popup doesn’t appear, select some different text, then re-select the desired text, and the popup will appear after a couple second delay.
See here & subsequent for more: