If I understand the steps correctly, I can't replicate that in Firefox 47. Step #1: Click a link to a movie title. The site launches a popup window with the results using a script: <code>window.open(''link'', 'priceWin', 'toolbar=no,scrollbars=yes,status=yes,resizable=yes,width=580,height=600')</code> The site re-uses the popup for future titles. Step #2: Click a price in the popup and the site opens in a new tab in the ''main'' window The popup re-uses the tab for other stores you try to view. '''With the default "tab instead" setting, the store page should not open in a third window.''' Could you re-test starting from a new window (Ctrl+n) in case there is something peculiar about the window you started in? ---- I noticed something interesting about this site because of a setting I customized. You can change what Step #2 does to opening a tab in the popup window instead. This involves blocking the site from hiding the full toolbar. If you want to try that, here's how: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button promising to be careful. (2) In the search box above the list, type or paste '''open_f''' and pause while the list is filtered (3) Double-click the '''dom.disable_window_open_feature.toolbar''' preference to switch it from false to true (meaning, disable sites from deciding whether the toolbar is visible) If you close the popup and launch it again, Firefox should display the full toolbar, and should open the store links in a tab in that same window.