USB Keyboard Issue in Set Top Box Android Kitkat 4.4

[Yossi]

I have a set top box Android Kitkat Version 4.4. I use USB Keyboard in my set top box, when I press Shift+Any Key (example Shift+A or etc) on EditText, mouse pointer change the icon.
When I want to delete any words, I cant delete the word using Backspace. Maybe Shift Key was locked. I can delete any words when I close the virtual keyboard and then open the virtual keyboard again using USB Keyboard.

Pointer Before Press Shift in USB Keyboard

Pointer After Press Shift in USB Keyboard

How to solve it?

Thanks,
Warm Regards