does someone has an idea, why the outputpanel "timeline" is not rerendered?
<apex:inputCheckbox id="budget" value="{!opp.Budget_available__c}" />
<apex:actionSupport event="onclick" rerender="pr, timeline" action="{!countPr}"/>
<apex:outputLabel for="budget" value="Customer has definded budget" />
<apex:outputPanel id="timeline">
<apex:outputPanel style="margin-left:3px;" rendered="{!IF(opp.Budget_available__c, 'true', 'false')}">
Timeline: <apex:inputField value="{!opp.Timeline__c}" />
</apex:outputPanel>
</apex:outputPanel>