hello...

i have a problem with internet explorer on my lumia 800.

since i updated to 7.8 tabs are not working.!
I hit the "new tab" and it does nothing.!
after that i have not the option to choose which search engine to have as default.
Anybody knows what to do?
also since i updated i think my phone lags a little..before the update it was going faster
(sorry for bad english)