I have a pageblock with a picklist that should trigger a rerender of a dynamic component in another pageblock when a value of the picklist is changed. Depending on the value I will create diferent  fields to populate the dynamic component. BUT the problem is that when I select one of the values in the picklist the entire page is refreshed and not the dynamic component. I checked the debug logs and the params are being sent to the controller correctly but for some reason the entire page is refreshing.

<apex:column headerValue="Line type">
                  <apex:actionRegion id="lnTypeRgn">
                      <apex:inputField value="{!SOI.Line_Type__c}" id="fLineType">
                          <apex:actionSupport event="onblur" reRender="detailBlock" action="{!dummyProp}" >
                                   <apex:param name="currSOIid" value="{!SOI.Id}" assignTo="{!currSOIid}"/>
                          </apex:actionSupport>
                      </apex:inputField>
                  </apex:actionRegion>
                </apex:column>

 CurrSOI would be the record in row being changed. The debug log show the ID is being passed correctly as well as the Line Type value:

these are the controller methods being invoked

 //Sales Order Item Detail Methods://////////////////////////////////////
   public PageReference dummyProp() {
    system.debug('###### CurrSOI: ' + currSOI);
        return null;
    }
   
    public  Component.Apex.PageBlockSection getLoadSOIDetComponent() {
       //Create teh dynamic component to populate with other components depending on the selected LineType
       Component.Apex.PageBlockSection section = new Component.Apex.PageBlockSection (collapsible = True,title = 'Sales Order Item Details: ',showHeader = True);
       List<Sales_Order_Item_Detail__c> SOIdets;
       system.debug('#### DETCOMP- CurrSOI: ' + currSOI);
      
       if(currSOI <> null) {
          //get curr LineType
          String lnType = getcurrLineType();
          System.debug('#### currLineType: ' + getcurrLineType());
          //validate which line type is selected and create the correct components:
          if(lnType == 'Course') {
              //load the required fields and also component to add contacts(course registrations)
              section.title = 'Sales Order Item Details: Course'; 
              Component.apex.PageBlockSectionItem pbsi = new Component.apex.PageBlockSectionItem ();
              //add the input fields of the SOI to the dynamic component:
              Component.apex.inputField courseNo = new component.apex.inputField(value = currSOI.Course_No__c);
              Component.apex.inputField courseStartDate = new component.apex.inputField(value = currSOI.Contract_Start_Date__c);
              pbsi.childComponents.add(courseNo);
              pbsi.childcomponents.add(courseStartDate);
              section.childComponents.add(pbsi);
              //then need to add a course registration component to link to contacts:
              system.debug('##### section: ' + section + ' -- ' + courseNo + ' - ' + courseStartDate); 
              return section;       
          }else if (lnType == 'Resource'){
               section.title = 'Sales Order Item Details: Resource';
               system.debug('##### section: ' + section);
               return section;  
          }else if (lnType == 'Item'){
              section.title = 'Sales Order Item Details: Item';
              system.debug('##### section: ' + section);
              return  section;  
          }
       }
        //it is a new Sales Order and therefore no SOIs loaded, send back null section
         section.title = 'Sales Order Item Details: NULL';
         system.debug('##### section: ' + section);
        return section;
    }

and this is a debug log written when the onchange is fired on the picklist. There is another debug log written immediately afterwards when the page is refreshed.

|DEBUG|#### DETCOMP- CurrSOI: SCRB_SalesOrderLineItem__c:{CurrencyIsoCode=DKK, ProductId__c=01tD0000002ZU9rIAG, Name=a07M0000000eOh4, Id=a07M0000000eOh4IAE, etc...
|DEBUG|#### currLineType: Course
|DEBUG|##### section: Component.apex.pageblocksection -- Component.apex.inputfield - Component.apex.inputfield

Can anyone figure out why the components are not rendering as they should????