Hi

I should be able to help you with this.

This problem can be caused by a lack of capcity on your device. First off, I recoment closing all the apps you have open. Your device should have three icons to go back, go to home and go to open apps. Tap this last one and close the apps you have open.

From the Android home screen, find the Settings app, typically with a cogwheel icon. Scroll down to Applications and find Firefox. Now tap Clear Cache (not Clear Data!).

This should resolve this issue, but if not, please come back here and we can look into a different solution for you.

My dear Seburo I trai everything by yours instruktion but soory nothing is beter .Stil i have black square on my displey /I forget to tell you that is samsung tablet pro with android 4.4?/. You was very frendly and profy and i prishieted you to trai to help me. Yours program on my pc is very good and i heve no problem /i use your firefox from begining many years and always i am satisfied/. Dear Seburo i will take sam other program for a some time and will back again be shore! Thx anyway arhitekt Boba ps sory for my english but i hope that you andersted me!