Ok, answering my own question. The answer is, No. Won't work - tried it, no change. But, did some experimenting. Found answer here in mozilla forum: [http://example.com https://support.mozilla.org/en-US/questions/1178312#answer-1030416] Just do 'about:config', then find ''''browser.newtabpage.activity-stream.enabled'''' and toggle to ''''false''''. Open new page, reorganize your tabs, then set ''''browser.newtabpage.activity-stream.enabled'''' back to ''''true''''. If you need more rows and/or columns to display the movable tiles, find ''''browser.newtabpage.rows'''' and ''''browser.newtabpage.columns'''' and set these to the values you need. In my own case, I needed/wanted 5 rows x 5 cols. This works for either ''''browser.newtabpage.activity-stream.enabled'''' = ''''true'''''' (non-movable tiles) ''or =''''false'''' ''(movable tiles)'', doesn't matter which. To set total # of tiles when ''''browser.newtabpage.activity-stream.enabled'''' is ''''true'''', find ''''browser.newtabpage.activity-stream.topSitesCount'''' and set to number that equals your rows x columns. In my case, 25. Hope that helps someone. Enjoy!