(X) copy/paste buffer overwritten by Firefox autocomplete/autosuggestion

Question

Firefox replaces the X selection with partial URL when it auto completes an URL typed in the Location Bar. How can this be prevented?

If I select some text with the mouse, I can then paste it somewhere else without explicitly copying it to clipboard using eg. mouse middle-click. If Firefox is used to open an URL by typing it in the location bar and the URL is auto completed, middle-click pastes the completed part of the URL.

As an example:

1. Select text to be pasted in Google Translate using mouse
2. Switch to a text editor
3. Press mouse middle button, the selected text is pasted
4. Switch to Firefox, open a new tab and start typing into Location Bar the URL to Google Translate
5. After few characters, Firefox auto completes the url, eg. type 'trans' -> URL is completed to translate.google.com/ with bolded part selected
6. Press enter, Google Translate opens
7. Move mouse cursor to input box, press middle mouse button to paste selection
8. The input box now contains "late.google.com/" instead of the text selected originally

This doesn't happen every time, but often enough to be really annoying.

Is there a way to prevent the Firefox completed part from being selected?

Edited to clarify the issue.

Answer 1

1. Disable autocomplete/autosuggestion.  (We had to destroy the village in order to save it.)
2. Access "translate.google" via a bookmark, so you don't have to type into the location bar.

Answer 2

If you'd prefer destroying a different village, you can try disabling clipboard.autocopy in about:config. This will disable automatic copying of selected characters to the X clipboard (you'll have to do Ctrl-C to copy), so the URL autocompletion won't overwrite your clipboard anymore. Pasting from the X clipboard to Firefox will still work.

Yes, this too is a workaround, the best solution would be if the FF folks would fix the autocomplete bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1215964