This is probably an easy solution, but its really frustrating:

The page is using a selectList to provide a value to the query in the controller. The query results should be displayed in a pageBlockTable, but the table isn't rendering when the commandButton is pushed. 

I'm pretty sure the select value is being set, and the query is firing as expected, but I can't figure out ahy the table isn't rendering: Here is the code:

public with sharing class CompController {

  public list<string> compNames {get; set;}
  public list<Comp__c> comps;
  public list<SelectOption> compList;
  public id selectedComp {get; set;}
  
  public CompController() {
    comps = new list<Comp__c>([select id, Name from Comp__c]);
    compList = getCompList();
  }
  
  public list<SelectOption> getCompList() {
    compNames = new list<string>();
    compList = new list<SelectOption>();
    for (Comp__c Comp :comps) {
    	system.debug(Comp.Name);
        compNames.add(Comp.Name);
        compList.add(new SelectOption(Comp.id, Comp.Name));
    }
    return compList;
  }
  
  public list<Comp_Control__c> Controls;
  
  public list<Comp_Control__c> getControls() {
  	return Controls;
  }
  
  public list<Comp_Control__c> setControls(id CID){
    Controls = new list<Comp_Control__c> ([select id, Control__c, Control_Category__c, 
                            Control_Number__c 
                            from Comp_Control__c where Comp__c = :CID]);
    return Controls;
  }
  
  public pageReference fetchControls() {
    setControls(selectedComp);
    return null;
  }
  
}

The page is here:

<apex:page controller="ComplianceController">
  <apex:form >
    <apex:pageBlock title="Compliance Control Check">
      Select Compliance <p/>
      <apex:SelectList value="{!selectedComp}" >
        <apex:SelectOptions value="{!CompList}"/>
      </apex:SelectList>
      <apex:commandButton value="Fetch Controls" 
                          action="{!fetchControls}" reRender="CompControls"/>
      <p/><p/>
      <apex:outputPanel id="CompControls">
          
        <apex:pageBlockTable value="{!Controls}" var="C">
          <apex:column >
            <apex:outputLink value="/{!C.Control__c}">{!C.Control__r.Name}
            </apex:outputLink>
          </apex:column>
          <apex:column value="{!C.Control_Number__c}"/>
          <apex:column value="{!C.Control_Category__c}"/>
        </apex:pageBlockTable>
          
      </apex:outputPanel>
    </apex:pageBlock>
  </apex:form>
</apex:page>

 Any feedback is appreciated