It is the one simplest function that makes me miss Chrome. It's so stupid and it makes No sense at all to have that function just to open it in a totally random tab.

Steps to recreate - in case you have never experienced it, yet. -

1. Select a text or url using your mouse.
2. Drag that text on the top of address bar where the tabs are.
3. You can drop it on a specific tab or an empty slot, it makes no difference to Opera and it opens your url or searches the text you're dragging in a totally random tab.