I'm sure this has been discussed before, but still wanted to chime in with my experiences.

With XanChat the only addon loaded, Edit Mode is tainted. This has already been noted.

What I am seeing is when other addons are loaded, Bartender4 as a prime example, XanChat is tainting Bartender4 to also be blocked from Edit Mode.

Should be noted that Bartender4, by itself, does not normally taint Edit Mode. I've noticed this also the case with Bazooka, various Pet addons, etc. None of these normally taint Edit Mode, at least not in a fresh /reload but when XanChat is also loaded all of these addons will be included in the taint.

I get no specific error messages, but no taint occurs when XanChat is removed, so no idea what the issue is but something with the addon is clearly causing something to happen.

It looks like any addon that sets the width/height or touches pretty much ANY element of the Default Chat Frame [1] in Retail causes a taint now because of Edit Mode. I went ahead and removed a bunch of code that does this for only retail. I've not gotten anymore taint issues, but if I find a new one, I'll remove it.

I was able to reproduce the issue with the latest patch. It appears it has to do with any addon touching the Alpha layers of the Chat Frame in any way. I suspect they are being extremely over protective of all the frames in their Edit Mode. I will look into this a bit more.

Let me know if the issue still happens with the latest version and with on xanChat loaded.

Also make sure you are using the latest version of xanChat 9.7

I'm not able to get these Taint modes errors on my end. I'll try loading Bartender myself and see if that causes it. I had originally fixed the taint issues on another ticket. To be fair, the new Blizzard Edit Mode is VERY buggy and lots of addons taint it. If you can provide the exact taint error that would be great.