Theme Editor is broken in 1.10
I don't know how old is this issue, but in the new Vivaldi 1.10.867.38 Stable 64bit release I'm not able to edit any themes without issues.
EDIT: Sorry I posted this a bit too fast a fresh profile seems to be the remedy only for a very short time.
@zaibon look in that thread again
I think it's not Theme Editor" broken. Missing tick occasionally happen to me on other places in settings. Unlike @nfsmaniac, I open Vivaldi settings in tab.
Just a few minutes ago, a simple Alt-Tab (change focus to other application) make tick on Startup settings can not be seen.
What I did to "fix" it, press Refresh > Randomly tick those check boxes. No guarantee money back if it's not working for any of you.
While we're still in Theme Editor issue.
It is color input that still forcing us 7 digits entry when we try to keyboard edit it.
I was testing various Snapshots now and the last working version seems to be 1.10.834.9.
Since Vivaldi 1.10.838.7 there's the issue.