I should preface this by saying I am pretty sure that Opera is not the problem, but I don't know where to look and what to do to try correcting this.
Machine specs- Mid-2012 Macbook Pro non-Retina, i7, 16GB RAM, 512 GB SSD, Running Mojave beta for 10.14.4. Browser is current Dev version.
With respect to the above specs, this has happened on several releases of all three versions of Opera- DEV, Beta, and Stable. It has been happening since Mojave 10.14.2. I have uninstalled and reinstalled Opera. Anytime I enter text- in other words, use the keyboard- I get the beachball and it takes forever to clear it. The text eventually makes it into whatever I was writing to, but it takes a long time- several minutes. During that time, the entire browser is off limits.
Since this has happened with many versions and I have uninstalled/reinstalled, plus it has happened through many releases of Mojave, I thinking this is something within my Mac itself- not Opera and not macOS. I'm using Brave for my browser on this machine for now, but would really like to get back to using Opera on it. Brave is a great browser, but Opera suits me more.
Does anyone have suggestions as to what I can try so I can clear this problem and get Opera going again?