EM_LIMITTEXT Exceeded Limit Issue

Do you know how to improve EM_LIMITEXT in the following two cases?

1. If you press ENTER while the input limit has already been reached, you can still enter a new line
2. With ATOK, you can still enter numbers freely (*) from the numeric keypad even when the input limit has already been reached by setting the following settings.

Settings: Select ATOK Properties → Input/Conversion Tab → Input Assistance → Make sure the input from the numeric keypad is half-width (T)

自由 Even though it is free, if the maximum limit is 256 bytes, you can enter another 256 bytes.

In particular, regarding No.2, I want to prevent EM_LIMITEXT from breaking the limit without changing the ATOK setting.