It revived the Android menu button. root is not required.
Let's regain the menu display of the app.
Further buttons can be displayed "Home" "Back" "Resents".
You can use as an alternative to the failed physical button.

[Basic functions]
 - Display of the menu buttons
 - The position of the button size transparency color customize the icon
 - Display of the notification bar
 - The presence or absence of vibration

[Official Twitter]
https://twitter.com/JetToastDevelop

[Other buttons]
 - back button
 - Home button
 - Application button recently used
 - Power button
 - Button to increase the volume
 - Button to lower the volume
 - Mute button
 - Enter key button
 - Space key button
 - Arrow key buttons
 - TAB key buttons
 - Page up button
 - Page Down button

[Application]
Buttons can be added freely you can customize the operation at the time of tap and long press.

[Keyboard switching]
When you press the menu button send the Menu key from the keyboard (IME) you call up the menu of the app in the display.
When you press the button if the keyboard is not a menu button IME because the keyboard selection is displayed
Please temporarily switching. Then when performing the character input will return the keyboard at the touch of a button.