Hardly works at all for me anymore.  Won't load correctly.  Slow.  Can't set as start page.  Tab won't stay pinned.  I've moved on to Speed Dial 2 extension - not quite as sophisticated, but it WORKS!!  It will have to do for now until FVD gets the bugs worked out.

Windows 7, Firefox 57.0.3 (64 bit), Speed Dial 64.3.5

No, it does open in a new tab.  When I open Firefox, I used to have Speed Dial & Gmail "pinned" (right click on a tab & choose "Pin Tab" - it then shows up on the left side as a "tiny" tab) so they would always load when I opened FF.  Now only Gmail shows up as a pinned tab when I open FF.  Another regular tab with my home page opens, which I now load SD into & then pin it.  But I have to do this every time I open FF.  THe SD tab won't "stick" like the Gmail tab.does.  It's not a huge deal, but since it used to work, I was wondering if I could make it work again.  Thanks.