I think I found a solution. In the left-sidebar menu, click WPAdmin. It opens a new tab with the desired icon.

Here's the situation:
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The left sidebar shows the desired tab icon (i.e., a black-and-blue Microsoft Windows icon). The tab itself just shows the default WordPress icon. Until a recent system change, the tab was displaying the desired icon. Now it doesn't. How can I persuade Opera to display that icon?

I saw somewhere that I might be able to restore the desired icon by clicking on the heart icon at the right end of the address bar. Clicking on that does display the default WordPress icon, but I don't see any way to direct it to the folder where I have stored a copy of the desired icon.

Oh. I do, now that you mention it. It's a search icon. It didn't occur to me that it would search tabs. I guess I must have assumed that it was for, like, Google search.

Alright. Micro-mystery solved. Thank you!

@leocg Thanks for the quick reply. The new button is what I'm talking about -- it's not there. I don't have a button that shows the list of opened tabs.

I'm using Opera in Windows 10. Previously, there was a button on the top bar that, when I clicked it, would show me a list of open tabs. It seems to have disappeared. I would like to get it back, but am not sure how.

I think it was part of Opera -- I haven't done much customizing -- but I'm not seeing any such option in Settings. I did look for extensions that would add that functionality, but the ones I saw would open a separate page or otherwise seemed clunky. The button I'm talking about opened the list as a drop-down, without going to any other webpage.

It looks like I'll have to disable each one individually there. It wouldn't kill me. It's just that this is not my first reinstallation. It's getting tiresome. But thanks for the suggestion.

I never use Opera's keyboard shortcuts, and I often find that they get in the way of what I do use Opera for. Is there a simple way to disable all Opera keyboard shortcuts?

I go to a Wordpress blog where, an hour ago, I was developing a post. I had a total of 14 draft posts under development there. Opera (recent or latest version, installed on Windows 7) has reliably shown me that list of drafts, but this week I am trying Opera Portable 47.0 x64 on a new (Windows 10) installation (same hardware). This version of Opera reported that it was unable to save my last draft, so I killed and restarted it. Now it says, "You don't have any drafts. Would you like to create one?"

Opening the same blog in Firefox confirms that the drafts are still there. It seems I can't display an image here, but the little pencil-and-paper icon at the top of the screen in Opera does have the number 14 next to it, and when I mouse over it, the tooltip confirms that this is the number of "Latest Drafts." When I click on the 14, I get "See all drafts (14)," and when I choose that, I'm back to this "You don't have any drafts" page.

I wonder if it happens only when Chrome is running. Isn't Opera built on Chrome, or something like that?

Anyway, I'm experimenting with Chrome shut down while using Opera. I'll try to remember to come back and report on results later.

That advice worked. Here's a writeup, FYI: http://raywoodcockslatest.wordpress.com/2014/07/01/wordpress-asks-are-you-sure/