Keeper Security Extension
Keeper security extension has stopped working for me in Vivaldi. It was working previously, and it still works in Chrome and Firefox. The exact symptoms are that I can't type into the email address and password fields to log in to the extension anymore. It simply doesn't accept input. I was using 1.3.551.17 (Developer Build) (64-bit) initially. I regressed back through 2 previous Dev Builds, and finally put 1.2 Stable back on, and it's still not working. I've tried removing the extension, clearing all Private Data, rebooting and reinstalling the extension. Still doesn't work. Really not sure how else to troubleshoot this, and I'm not sure Keeper support will support it on Vivaldi.
Okay, I got it fixed finally, but I had to go back to square one to do it. I had remove ALL extensions, clear out ALL cached information, uninstall Vivaldi, delete any residual folders, then reinstall and reconfigure everything. Now it works again. I wish I knew what caused the problem.