country code is replace with default country code when we are backspacing to clear only number

[Kamiyab Asamadi]

Hello,
currently country code is replace with default country code when will backspacing to clear only number. as soon as fist digit of number is clear it is replace default country code but I want to stay country code as its user input
example
default country +971
if input +91 94
and if I clear only 94 to change different number country code also set to default country it is very bad user experiance