Problem typing

We have a dynamic form, and we have realized that when we type fast on any field, some pressed keys are not transfering into the field, so some characters are lost
What can be causing this?

Thanks in advance.

Regards.


We are working under:
v9.0p_2013-08-20/PowerEdition Development SC and IExplrorer 10.0.9200 navigator, Eclipse Helios and Tomcat 7.0.28