JS 4.0.0 - values for dates dissapearing from input dialog box

[robidomadenik]

Hello.

I have a question regarding JasperReport Server version 4.0.0......
I made a report, which has a few input parameters, two of them are dates (DatumOD and DatumDO).
In JSP file DefaultParametersForm.jsp a made a customization, so that I added 3 buttons (<INPUT TYPE="BUTTON") which have an OnClick event (the click of a button fills the DatumOD and DatumDO field with values for the current month, next and previous month ).

But when I move to the next TextBox field (Konto (Terjatve)), the DatumOD and DatumDO fields are beeing erased!!
If I fill them with DateTime Picker component the values stays there and are not beeing erased.

Please, If someone could help me with this one....... Thanks!

Best regards,
Robi