FVD Speed Dial
Seems this extension just doesn't work. I have followed some of the workarounds to get it set as my start page and new tab page and that works although it is a little clunky. Where I have the main problem which makes it unusable and keeps me from making Vivaldi as my default browser is that I have my dials set to auto refresh at various intervals. When they do this Vivaldi appears to go full screen then open new windows for the dial link as it tries to update it, this causes Vivaldi to flash as it updates and makes each window unusable. Not sure whether this is Vivaldi or the extension but it is usable in Firefox/Chrome. I'll keep checking back. I have the 1.3.x latest version but have had this problem.
I've used FVD for almost one year w/o big problems.
Anyway now I,m using Simple Speed dial.