Strange behaviour of Edit Box when inputting values

[bachra]

Hi ,
I am using Visual C++ to write and application which reads and write to a smart card (dialog based app.)
Everything seems perfect unless the following problem:
I used a timer to check the presence of card every one second.
But If I try to input a value in any edit box in my form
(Dialog) the cursor behaves strangely and any time I input a character it is duplicated (*10) and I cannot control it.

Thank you for help.

Bechir