I have created a VF page that has a custom button as a part of it. When I click the custom button, I want the new page to open in a new window. When I am logged in, this works. When other uses are logged in and the button is clicked, it opens the new page like it is embedded in the VF page.

Here is my code:

<apex:page standardcontroller="Wire_Center__c" tabStyle="Sites__c" extensions="RFMDU">
    <apex:pageBlock >
                <apex:pageBlockTable value="{!Sites}" var="zip" width="100%" columns="5">
                <apex:column id="c7">
                    <apex:form >
                    <apex:commandButton value="Assign" onclick="javascript&colon;openPopUpWindow;return false" action="/a1E/e?CF00NC0000005bqW8={!zip.name}&CF00NC0000005bqW8_lkid={!zip.id}"/>
                    </apex:form>
                </apex:column>                
                <apex:column id="c5" headerValue="MDU">
                    <apex:outputLink value="/{!zip.Id}" target="_top">{!zip.Name}</apex:outputLink>
                </apex:column>
                    <apex:column id="c4" headerValue="Last Resweep">
                        <apex:outputField value="{!zip.Date_of_Last_Resweep__c}"/>
                </apex:column>
                    <apex:column id="c3" headerValue="Current Penetration">
                        <apex:outputField value="{!zip.Current_Penetration__c}"/>  
                </apex:column>
                    <apex:column id="c2" headerValue="Non-Video Doors">
                        <apex:outputField value="{!zip.Non_Video_Doors__c}"/>                      
                </apex:column>          
                </apex:pageBlockTable> 
    </apex:pageBlock>
</apex:page>

Any thoughts?

Thanks in advance,

Matt