<apex:page standardController="Event" extensions="ext1" showHeader="false" standardStylesheets="false">
    <apex:form >
    <div style="margin:0px; overflow:auto">
      <apex:pageBlock rendered="{!list != null}">
         <div style="overflow:auto;">
          <apex:pageBlockTable value="{!sublist}" var="s" rendered="{!sublist != null}" width="100%" styleClass="overflow:auto">
            <iframe scrolling="yes">
              <apex:column headerValue="Activity">
                  <apex:outputField value="{!s.name}"/>
              </apex:column>
              </iframe>
          </apex:pageBlockTable><br/>

          <apex:pageBlockTable value="{!sList}" var="s" rendered="{!sList != null}">
              <apex:column headerValue="List">
                  <apex:outputLink value="/{!s.Id}" target="_parent">{!s.Name}</apex:outputLink>
              </apex:column>
          </apex:pageBlockTable>
        </div>
      </apex:pageBlock>
    </div>
    </apex:form>
    </apex:page>