User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:48.0) Gecko/20100101 Firefox/48.0 Build ID: 20160322030417 Steps to reproduce: Create tab using browser.tabs.create in an extension. Close the tab created. Actual results: The tab that gets activated isnt the originating tab but instead the next one on the tabstrip. Expected results: The originating tab should get activated. Here is an example extension: https://addons.mozilla.org/en-US/firefox/addon/context-duckduckgo/ I had to do a hacky workaround by creating the tab before the originating tab on the tabstrip so that closing the tab with the search results would return me to the originating tab.