[Accessibility] - Special characters windows not accessible at all

When pressing F2 in text input mode, the special character windows come up, but can't be navigated at all. Also, all screen reader functions are disabled, and I can't go to other places in the score. The three tabs should be working as a standard dialog with three tabs, and the characters should be navigated using cursor. Musical symbols should have their text names such as flat, sharp, natural, so that we can know what they are.

Haipeng