Do you mean, you click a link and Firefox adds a new background tab, and you do not want Firefox to load the page into that tab until you activate it?

I'm not personally familiar with any extensions that do that.

Maybe there's an extension that will save URLs for future loading, and you can access the queue and load a saved URL when you get around to it. Perhaps there wouldn't be individual phantom tabs on the tab bar, but as long as the list is nearly as convenient to click?? (And preferably stored securely, in light of the complaints in the reviews for BarTab that the pages were not listed in session history as tabs that could be restored after Firefox crashed.)

Or maybe searching with different keywords turned up something you'll like:

https://addons.mozilla.org/firefox/addon/load-tab-on-select/

If you try it, please report back on whether it accomplishes what you need.

Meanwhile found BarTab Heavy and BarTab Plus (and the latter seems to work fine really not loading anything in background tabs until that tab is selected, even for session manager reloads of many tabs). https://addons.mozilla.org/en-Us/firefox/addon/bartab-plus/ Have saved your suggestion gratefully (did nt find it myself, so many thx) and will try once necessary.

Also found a replacement for old Download Statusbar: https://addons.mozilla.org/en-US/firefox/addon/s3download-statusbar/

However, comparing performance with FF21, the new versions are all much slower, especially with many tabs open. Assuming the web is more standardized now and programming got optimized, it is unclear why that is, but am not an expert and hence guess I am missing a lot. If I had a say, I would suggest to go back to FF21, treat everything that happened since then as learning experience, avoid Chrome & IE mistakes and build a better browser, but that is most likely naive and a joke in your eyes, though it should be power users who steer development, neither developers nor average users ;)