I already asked this in the Opera for Windows forum but was redirected to this subforum instead, since I am using the Opera Developer version.

Normally you could get rid of default search engines by deleting or emptying the default_partners.json file in the opera folder and all of them except google would not show up anymore.
However with the most recent update this approach does not work anymore. Is there another way to remove the default searches (or at least change their shortcut?). They are colliding with my other, custom searches.

Help very highly apprechiated. Maybe the Opera team can add an option to at least change the shortcut letters for the default searches. Thanks.

Sadly this won't work.

"I can't remove the default search engines anymore" meant, that this does not work for me in the most recent version. There is no default_partner_content.json-file, but the search engines are there nonetheless.
I had a script that automatically removed this file upon every start of Opera (so that updates wouldn't bring search engines back), so I can't tell if the json even exists in the most recent Opera Developer version or if they ditched it and integrated the stuff from it somewhere else.

I can't remove the default search engines anymore and it is still not possible to change the letters for the default searches. Is there a way I can get rid of the default search engines in version 32.0 (opera developer)? They are colliding with my custom searches and I hate it.

Do I need to download another browser?

I was trying to play audio in a web app (javascript). It somehow does not recognize or trigger some notification when the audio finished playing as it would in other browser. Sorry, I don't know further specifics.

See also:
https://www.scirra.com/forum/viewtopic.php?f=152&t=128690

Just wanted to mention that the extension "modern scroll" can bypass the problem by implementing it's own middle mouse button scrolling. Can even set it to stop at mouse wheel scrolling, like it was in Opera 12.16, which is definitely a plus, too.

I don't have this problem with 22.0.1471.40, Win 8.1 64bit. Tried reinstalling and updating the Flash Player and Opera (or maybe try out Opera Next)?

Sure mate.

Version: 22.0.1471.40 - Opera ist auf dem neuesten Stand

Update-Stream: Next

Betriebssystem: Windows 8.1 64-bit (WoW64)

I also captured a video so you can see what happens:
https://www.youtube.com/watch?v=t9moDmfv_-8
Note I only click the middle mouse button once each time. Somehow it removes the scroll after a short time when you don't wait a bit before moving the mouse up or down.

When you click the middle mouse button and then move up your mouse up or down very fast, the page only stutters into the direction for a very short moment and then stops scrolling immediately.

Expected behaviour would be that it keeps scrolling up or down. (like in Opera 12)

Do note, that the problem only exists, when the time between middle mouse click and moving the mouse is relatively small. If you wait half a second, it will scroll flawlessly as expected.