} else if (event.key === tui.keys.switch_to_study) {
tui.switch_mode(mode_study);
} else if (event.key === tui.keys.switch_to_password) {
} else if (event.key === tui.keys.switch_to_study) {
tui.switch_mode(mode_study);
} else if (event.key === tui.keys.switch_to_password) {