So, I have code on that works perfectly in Safari. When the function is called, it creates a sized window to the a fraction of the size of the screen (code at bottom of post). The only issue is that the end-user(internal tool) of this code works in Chrome, and they report strange behavior (that I can replicate in my own machine on Chrome), in which the desired window is present and in the correct size.

However, it also creates an additional, unwanted tab of URL equivalent "about#blocked".

As this point, I'm pretty sure the issue lies in Chrome (and probably its security features) seeing as it does not occur on Safari browser.

Is there anything that I can do, in either code or instructions to the end-user to change their Chrome settings so that this tab does not get generated? Hopefully something that I've overlooked completely, being a Javascript novice.

function openAttachmentInNewWindow(recordIdToOpen) {
                var file_url = '/servlet/servlet.FileDownload?file='+recordIdToOpen;
                var params = [ 'height='+(screen.height/2),
                                'width='+(screen.width*3/4),
                                'Resizeable=yes',
                                'fullscreen=no' // only works in IE, but here for completeness
                            ].join(',');
               window.open(file_url, recordIdToOpen, params);
            }