Now suppose I want to select and paste this address, and click at the right edge of the displayed "URL." This is the result:
As can be easily seen in the image, if as user is not careful, a critical portion of the URL is lost. Even an attentive user still must repeat the select operation. Either way, time and effort are wasted.
Fortunately, though this is a bad UI decision, there is an option to force Opera to correctly display the URL correctly. Navigate to Opera|Settings|Advanced|Browsing. The penultimate checkbox under this tab is Show full web address in address field. Check this and the address bar will function correctly:
Similarly, Firefox no longer displays URLs correctly. The fix is here.