Goto the URL opera://settings/searchPopup, and disable the search popup.
Then, install https://chrome.google.com/webstore/detail/multiple-selection/cnccnjdknbhcdcenjmelmlkpklbhlieg/.
Then, click the cube icon at the right of the address bar and pin the extension to the address bar.
Then, click the extension's icon in the address bar and choose to turn the extension on.
Then, you can ctrl + left-click and drag to select multiple runs of text. Then, hit ctrl + c to copy.
Not perfect, but it works in my simple testing.
