I’ve got a Facebook App that I’ve created. I want it to be 760 px. wide however it seems to be stuck at 520 px. When I view the source generated by Facebook I see this.
<-- <iframe name="app_runner_fb_https4fa04becb1d045950954937" id="app_runner_fb_https4fa04becb1d045950954937" style="width:520px;height:800px;" frameborder="0" src="https://s-static.ak.facebook.com/platform/page_proxy.php?v=4#app_runner_fb_https4fa04becb1d045950954937"></iframe> -->
That seems to indicate that it is using 520. Yet, the settings seem correct in the Advanced Developer panel.
Using Google I see a bunch of reported problems from years ago with 760 px; however, the option is still in the settings. Does this option work? Recently Facebook moved pages to timeline which freed up the left nav-bar. My app looks stupid without that space taken. It sits in the center of the page with 100+ white pixels on each side.
That screenshot is a setting for the width of your canvas app (apps.facebook.com/something), and the options are fixed to 760 or fluid width (which is dependent on your own CSS too, of course)
However in your post you mentioned Timeline and Pages, which implies your app is a page tab app accessed as a tab on a Facebook page.
If that’s the case, the width setting which applies isn’t there, it’s under Page Tab on the front page of App settings and can be set to either 520px or 810px