I'm not a heavy-user of braille, but a client came up with a veird problem yesterday. They weren't able to compose a mail using a Focus 14 braille display. I can reproduce the issue with a Focus 40.
I have an iPhone 6 with iOS 9.2.
Steps to reproduce:
1. Open the Mail app.
2. Select the Compose button.
3. Now you should be placed in the to field, ready to write.
4. Write a mail address or just a few characters. You can see the text coming up just beautifully on the braille display.
5. Try to advance through the screen with the rocker bars on top of the Focus or with the regular command Space + Dot 4. Note that nothing will happen; you'll only hear the "bonk" sound.
6. If you explore the screen itself with your finger, you will notice that no text has been written into the To field and that the braille display won't follow when the focus changes.
7. By pressing Space+dots 1 and 2 you can get out of this freeze, and after that the braille display will be usable again, but the To field is still empty and if you start typing into it again, this same problem will occur.
Can other users confirm this? Will it occur only using the Focus or also with other braille displays? Have you found any work-arounds?