Currently you can only dismiss the popup by clicking on the small X. Wow popups are generally closed with a right click, such as the talking heads in world quests. NPC Scan also has this feature to dismiss it, it would be easier to dismiss some rares instead of using the very small X button. Thanks

Hi! I had the same interest so I wrote code for this and have it in my own personal addon script/folder. Hopefully, you or anyone can use this code to get that functionality! I am not sure if it's 100% bug free, but it works for me!

Note: I don't think it can be dismissed in combat but don't have silverdragon popping up in combat anyways.

if SilverDragonPopupButton then
  SilverDragonPopupButton:SetScript('OnMouseDown', function (self, button)
    if button == 'RightButton' then
            SilverDragonPopupButton:Hide()
    end
  end)
end

I looked into the silver dragon code and I am not very familiar with Ace3. I added an item to the list of configs but, I am able to figure how to access that value. Then, it could check if the right click option is enabled before checking for right clicks on the popup. If I figure that out I will add a comment. Here is what it could look like in the addon interface options: