I have set Opera as the default browser on my PC, which runs Windows 7. When I click on a email link in Outlook, it opens in IE.
If I change the default browser to Google Chrome or Firefox, the links do open in these browsers. It's just Opera that does not behave like a default browser as far as links in an email go.

My email program is Microsoft Outlook 2013 running on a Windows 7 Pro machine. I have set Opera as the default browser but when I click on a URL link in an email, it opens in Internet Explorer instead.
I then set Firefox (the other browser I have) as the default browser and the link opens in Firefox, not IE. I reset the default to Opera but the link will now open in IE.
What do I need to do to get it to open in Opera?