@leocg So, I googled some more.
And I found a tip I should probably have done from the beginning.

Which is to try another mouse, and I did.

I probably should have done that before I started re-installing my mouse drivers. xD

Anyway, it is an old mouse. Served me well for years.
So it's probably time to get a new one anyway.

Strange it only happens in Opera, but it's probably only going to get worse.

Thanks for your help at least!

@leocg I didn't consider that. As it's still working as in intended for other apps/on the desktop.
The context menu only shows when I release the right mouse button. Like normal.

But I checked the settings, just in case. And I didn't find any option related to when the context menu should show on a right click.

So I tested it to make sure, again. And now something else is happening. When I right click, and hold. The context menu appears, then goes away. Then when I release the right mouse button, it shows up. Like normal.

So it appears this may not have been the correct place to post for help.

Edit:
So now it's back to the first way again. I really don't know what's happening here. It was also fine for a second. Even in Opera. I could use mouse gestures like before. But now it's back with the context menu again.
And it's fine in other apps, and on the desktop.

The problem:
When I hold down the right mouse button. The context menu opens.
Blocking mouse gestures if I move the mouse over it.

I can still use mouse gestures, to an extent. As long as it does not move over the context menu. Which is sorta hard to do.

What should happen:
When I hold down the right mouse button, the gestures circle should show up. Or if I hold and release, then the context menu should show up.

This is the way it's been for years, up until yesterday.

What I have tried so far:

• Restarting.
• Disabling all my extensions, then restarted.
• Disable then mouse gestures option, then restarted.
• And enabled again, and then restarted again.
• Googling, I didn't find anything relevant to my situation.
• Tried looking on the forums here if anyone else had the same issue. Again, didn't find anything relevant.

Version: 52.0.2871.64 - Opera is up to date
Update stream: Stable
System: Windows 10 64-bit

Any help would be greatly appreciated on this.
And if there is any more info I could provide, then I'll do my best to supply.

Thank you!