I entered the address of my favourite and selected "Menu>Page>Pin to TopSites" but it doesn't get pinned (popup message says so, but it isn't).

Hello there I have set the Firefox Homescreen on my Android phone with my Top 8 Websites, which is a very nice feature. Sometimes though the order gets mixed up and recently a site I don't want showed up instead of the usual. I entered the address of my favourite and selected "Menu>Page>Pin to TopSites" but it doesn't get pinned (popup message says so, but it isn't). I then tried to free up a Pin by "long press>delete from History", just o have the next unwanted Website-Pin show up (from browsing history I assumed). So I deleted all private data in "settings" and selected "Privacy>Clear private Data on exit", even stopped the App manually and repeated the deleting. TopSites still remembers and opens Pin after Pin from visited Websites (deleted 100+ Pins and got 100+ new ones from Sites I've been) How to delete (really delete/wipe/burn to dust) this History ?