Previously I would click the retweet button, then choose "Edit and Retweet".
Then I could prepare the tweet and it would show up as a "mention" in the retweeted person's "mentions" column.
Now Tweetdeck affords no ability to accomplish that.
If you use "Quote Tweet" you can comment on it, but the person whose tweet you're quoting won't know. Hence, NO DIALOGUE.
This makes me sick.
Here's the workaround and it's a pain:
You must type in the twitter handle of the person you're "quoting" if you want it to wind up in their mentions column.