You could also get rid of the top separator so it doesn't look odd with the line at the bottom in the second image by adding code below.

#fd-separator1 { display: none !important; }

or for the below separator.

#fd-separator2 { display: none !important; }

regarding

@namespace url(http://www.w3.org/1999/xhtml);

@-moz-document url("chrome://fastdial/content/fastdial.html")


you cannot make a context menu within a html page, only if you create and addon with context menu instruction so it would come under firefox xpi.

In prefences when scrolling for number of columns or rows do not have the number 0 (zero) available.
This will then save the null error that insues.

Thanks