I can second this bug with the latest Firefox version 56.0 (64-bit), and FVD Speed Dial 62.4.8.

I would second this, I have been troubleshooting some issues that having access to the beta release might settle.

Thanks for all the hard work, on getting this updated being it is a free extension :)

Not within FVD Speed dial itself, more of a side effect but the copy URL function of the FoxyTab extension.  I just noticed it the issue or conflict maybe started with that last firefox update?  It is interesting.. I do not know anything about Firefox addon code but thought I would mention it as a since I noticed.  

I would love to help bata test the latest WebEX legacy.  Right now when the latest version on AMO breaks some function in the extension FoxyTab. 

Well running version 23.3.1 of FVD Speed Dial, and FoxyTab version 2.7 the copy URL function breaks.  When FVD SD is disabled the copy URL function works once again.