Issues with tumblr in latest snapshot..
When I'm on tumblr, the web page locks up quite often when scrolling on dashboard or through my likes. Sometimes just trying to log in. I can click other tabs and do things in them, return to the tumblr tab and it'll still be locked up. It eventually unlocks and I can use it again, but it's quite an annoyance. Haven't had this happen before. Works fine in other browsers. On mac, el capitan
A-ha! I have a similar problem. Didn't realize it was tumblr related, but you're right: it seems to be.
When locking happens, what does your Activity Monitor look like? Is fontd hogging the system? It is on my machine.
Strangely, this is only happening on one of my two Vivaldi installs. Only at work, not at home.
Here's my topic about the issue:
With the latest snapshot 1.0.385.5, I haven't encountered this problem anymore.