I'm a Salesforce newcomer. I'm trying to get some basic functionality working, based on the Introduction to VisualForce tutorial on Pluralsight.

The page is a list view:

    <!--Tree Search -->
    <apex:page standardController="Tree__c" recordSetVar="trees">
        <apex:form >
            <apex:pageBlock title="Tree List">
                <apex:inputField value="{!Tree__c.Status__c}"/>
                <apex:commandButton action="{!save}" value="Update"/>
                <apex:pageBlockTable value="{!selected}" var="tree">
                    <apex:column >
                        <apex:facet name="header">Tree ID</apex:facet>
                        <apex:outputField value="{!tree.Name}"/>
                    </apex:column>
                    <apex:column >
                        <apex:facet name="header">Status</apex:facet>
                        <apex:outputField value="{!tree.Status__c}"/>
                    </apex:column>
                </apex:pageBlockTable>
                    <apex:commandLink action="{!previous}">previous</apex:commandLink>&nbsp;
                    <apex:commandLink action="{!next}">next</apex:commandLink>
            </apex:pageBlock>
        </apex:form>    
    </apex:page>

A List Button has been added to the custom object:

![Update status graphic][1]

However, when I select objects from the Custom Object's tab (in this case "Trees") and click "Update Status". I get redirected to a blank page.

I'm expecting to see a list of all the records I just selected.

The page works 

Any ideas?

  [1]: https://i.sstatic.net/7dXcT.png

Browser: Chrome Version 34.0.1847.131 m
OS: Windows 7