You can open the Opera Menu left top by clicking on the most top left pixel, but you can't close the same menu with the same pixel.

See this quick video I've made.

Also, when you want to open a new tab you gotta click rather precise on the + next to existing tabs. If you click all on the top (which works in Firefox) nothing happens:

If you move your mouse cursor 3px lower you can open it:

If you compare that to Firefox:

you can see that it requires way less precise mouse targeting to trigger the + new tab button, which is prefered.

You can open the Opera Menu left top by clicking on the most top left pixel, but you can't close the same menu with the same pixel.

See this quick video I've made.

Also, when you want to open a new tab you gotta click rather precise on the + next to existing tabs. If you click all on the top (which works in Firefox) nothing happens:

If you move your mouse cursor 3px lower you can open it:

If you compare that to Firefox:

you can see that it requires way less precise mouse targeting to trigger the + new tab button, which is prefered.

I had a similar problem. It was getting better for me after I disabled the following flag:
opera://flags/#enable-async-dns
Maybe it's worth trying it on your machine.

This worked for me as well. It's now back to near-instant, as it should. What the heck does async DNS has to do with this? So weird. And isn't an asynchronous process supposed to NOT hang the system while it's waiting for whatever it's waiting?