Forms :: Stack Canvas Hides While Validation Of Any Item Is Failed On The Form?

i have a form based on tab canvas. for some values(on form) i am hiding some fileds or a complete frame on the form using stack canvas. it works fine but if a user enters a wrong value in some field i.e enters character in number field the stack canvas hides(showing the hidden fields).

I tried to use on error trigger at form level and when validate item trigger to show the canvas but it first hides the canvas once right value is entered it just shows canvas again. following is the code i wrote

IF MESSAGE_TYPE = 'FRM' AND MESSAGE_CODE IN ('40209','50016')
AND :SYSTEM.TRIGGER_ITEM IN (some field)
THEN
IF other_item_value = 'E' THEN
SHOW_VIEW('STK_CAN_ARL_INFO');
END IF;

I need not to hide the canvas in any case whether any other field on the form is validated or not.