Half black screen. Non responsive link. After upgrading to version 26 on Android 2.3.6

Hello. I had firefox 14 installed on my Samsung Galaxy Ace Plus- Android 2.3.6. Everything was working properly untill i upgraded to firefox version 26. Suddenly when i request a web page, either it is blocked with a half-black layer at the half bottom of it, which is not clickable. So if i need to see something at the bottom i have to use some difficult way to scroll upper part of page. Or. The web links are totally non responsive. It's like there is no link in the first place. I don't understand sometimes the need for such updates which cause a major drawback to firefox, when the older version is completly working perfectly. regards, Walid