I have found a work around and “band-aid fix” for this problem. Depending on your circumstances and the reason why you want the top sites hidden, this may or may not help you.
I’ll be straight up and say I have 1 particular folder for porn bookmarks. I have a about 15 folders of bookmarks and if you scroll down you’ll see one labeled “PRON”!
Now, the problem with the top sites on my phone’s mobile firefox was that all of the porn links were easily seen from the top sites list.
I recently downloaded an add-on for desktop firefox called “Link Password”. This adds a right click context option to your bookmark menu. I right clicked on the PRON bookmark folder and chose “Encrypt All Links In The Folder”. This allows you to password those links so no one else can open them. There is also a “Rename Links” option that will rename the links to random, docile internet names (Yahoo Login! Facebook App! Movies – Wikipedia! Those are some examples of what my raunchy porn link names turned into).
When I want to actually “use” those links, I just right click on my PRON bookmark folder in the bookmark menu, choose “DEcrypt All Links In The Folder”, put in my password, then they are usable again and their names are restored. When I’m done, Encrypt them again.
Now to the topic at hand, when the folder is encrypted, NONE of those porn bookmarks show up in my top sites list on my mobile phone’s firefox! You also can’t use the porn links on the phone itself since the “Link Password” add-on doesn’t exist for android firefox so the links just don’t work but that is JUST FINE with me.
Now I can hand my phone to a friend or family member without them accidentally seeing that stuff, or without snoopy friends or strangers at a party seeing that stuff.
There is just no way for them to see the actual names of the links or to even click on them.
So, if your issue with the top sites list is similar to mine, consider the “Link Password” add-on extension for the PC version of firefox and then you can keep sync turned on between your android and PC safely and with peace of mind once again!