How to cancel popup-close when pressing OK Button

Hi all,

I have a disturbing question within WebDynpro.

What i want:

Keep the popup screen open when the inputfield is initial or if the value is wrong (on domain level). (3 values on domain level: low, medium, high)

What i did:

I Create a popup and subscribed an action to the ok button:

wd_comp_controller->go_popup->subscribe_to_button_event(
button = if_wd_window=>co_button_ok
button_text = 'Ok'
action_name = 'ADD'
action_view = lo_view_controller
).

Within the onactionadd method i have placed a breakpoint but the program doesnt get past here if the inputfield is initial or if the inputfield has a bad value:

METHOD onactionadd.
ENDMETHOD.

When i leave the inputfield on the screen blank with

DETERMINED INPUT HELP: Z_MY_DOMAIN

TYPE OF INPUT HELP: fixed values for domains

Then when i push the Ok button it just closes the popup.

I Tryed to make the inputfield mandatory and use the next method within the WDDOBEFOREACTION:

CALL METHOD cl_wd_dynamic_tool=>check_mandatory_attr_on_view
EXPORTING
view_controller = lo_view_controller
display_messages = abap_true
IMPORTING
messages = lt_messages.

but even that diddnt work :/