Beta v34 did not fix my problem.

Mine occurs solely whenever I have DevTools open while at the same time the Device Mode toggle is set to a mobile device as viewport.

Only my keyboard (and not my mouse) stops responding. That applies to the entire site I'm viewing with mobile viewport emulation but also all other input elements on all of the other tabs as well! Except the address bar, thank God. The problem seems to be limited to that; when I press the toggle again and click on the refresh button (F5 doesn't work yet) at least the keyboard responds again. But as things are right now, I am unable to test adjustments to websites for whom I'm updating their mobile versions and see the result instantly. Pretty annoying.

Beta v34 did not fix my problem.

Mine occurs solely whenever I have DevTools open while at the same time the Device Mode toggle is set to a mobile device as viewport.

Only my keyboard (and not my mouse) stops responding. That applies to the entire site I'm viewing with mobile viewport emulation but also all other input elements on all of the other tabs as well! Except the address bar, thank God. The problem seems to be limited to that; when I press the toggle again and click on the refresh button (F5 doesn't work yet) at least the keyboard responds again. But as things are right now, I am unable to test adjustments to websites for whom I'm updating their mobile versions and see the result instantly. Pretty annoying.

I have noticed the exact same thing, dan1ellz. I have a self-written webpage on my localhost where the content scrolls in to the screen from the far left to the middle, like some tablet apps do. However on this computer, the delay is around 30s. It takes exactly 30 seconds before this css keyframe animation is even started!

I've tried everything. Nothing I did could make Opera 27 behave properly. Sometimes on a fresh install it would behave for like 2 or 3 times, but then it would revert to the same delay as before. The only thing that worked for me was to install the older version of Opera, 26, and after that I had to BREAK the auto-updater by renaming it. So that I will stay on v26 until this problem is sorted out. I can recommend that you try this. Because this problem does not exist for me in v26. Opera Devs, if you are reading, that is why updates should always be initiated by the USER and never ever ever be fully automated! If you need some info about my system config, feel free to contact me.

The updater is found at
C:\Program Files (x86)\Opera\current version number\opera_autoupdate.exe