SSRS report - Parameter field loses properties after initial run using UIBuilder class, help?

Hello, I'm creating a SSRS report in AX 2012 using DP, Contract and UIBuilder class, however I have a problem, there're two multiselect parameter fields being populated with a query to create a lookup, both of them displays the lookups, the checkboxes, and I can select the items I need to run the report, however, one of them, after I run the report, loses all its properties, does not display the lookup anymore, the length of the field is not the same, and I don't know why since the other one which works fine even after the initial run has been created the same way, here's the code on build and postRun methods in the UIBuilder class:

public void build()

{

   myContract= this.dataContractObject();

   commodityField = this.addDialogField(methodStr(reportContract, parmCommodityId), yieldContract);

   commodityField.lookupButton(FormLookupButton::Always);

   commodityField.displayLength(25);

}

public void postRun()

{

   Dialog dialogLocal = this.dialog();

   myContract= this.dataContractObject();

   dialogLocal.dialogForm().formRun().controlMethodOverload(false);

   postRunCommodityField = this.bindInfo().getDialogField(this.dataContractObject(), methodStr(reportContract, parmCommodityId));

   postRunCommodityField.registerOverrideMethod(methodStr(FormStringControl, lookup), methodStr(reportUIBuilder, commodityLookup), this);

}

Thanks in advanced!!