Bugs I have Noticed
Change the speed dial background go to "C:\Users\name\AppData\Local\Vivaldi\Application\126.96.36.199\resources\vivaldi\resources\bg.jpg"
Rename the image "bg" and add a plain colour image and name it "bg". I size it 1750 x 1280. You have to re-do it with each update.
If you just rename the bg.jpg file and nothing else you get a white background …...I think.
Close Vivaldi before doing this.
Oh! I've just noticed you use Mac, probably doesn't apply then
Thank you so much for that!
You can do a similar thing using a mac: Applications ▸ Vivaldi ▸ Contents ▸ Versions ▸ 188.8.131.52 ▸ Vivaldi Framework.framework ▸ Resources ▸ vivaldi ▸ resources ▸ bg.jpg
Replace and restart and your background image should have changed.
And for now you can middle-click or Ctrl+click on a link to open in background tab.