Black Background For Bookmarks FF57

[Tmod]

Hi,

New here and I have a custom theme OS Tiger X to be exact on Win10 1709 that I like the looks of but when scrolling the bookmarks in FF57 I get a black background and the bookmarks will be highlighted with a medium blue color much like the header of this forum. I had tried a different Aero 7 theme and it worked fine so it is the Tiger X theme.

Any ideas from anyone as I am a newbie with this here.

Thanks!!