I have an issue with my BB 9300. When typing (texting) a small box appears in the top right corner of the screen possibly with an arrow or an x- can't tell because it's too small for me to see. While that box is present my BB delays (freezes) while I'm typing. I have the latest OS installed. I have tried pulling the battery, reinstalling the OS and pulling the card. Also, a white screen appears on occation.
I have removed all apps that I have downloaded. I have dropped the phone once getting out of my car but that was a year ago so I don't think that would affect my BB now. It has never gone for a swim.
Sounds like that's the Predictive Text helper trying to anticipate the word you're typing. You can turn that off in Settings but I'm not sure exactly where. Shouldn't be too tough to find though.
The thing you're seeing in the top right corner is the data download/upload arrow symbols. If the device is busy sending/receiving data, it can cause some lag.
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