If I try to change the page settings of the page that is currently loaded, the Page Settings dialog box pops up underneath the Page Selection Bar. This isn't app-breaking as you can still access all the features - you just can't see the text boxes for page size (While not visible, you can still access the boxes to type in them).
If you leave the Page Settings dialog box open and then load a different page, the page selection bar will rise out of view and will no longer be obscuring the upper portion of the dialog box so you can read the dimensions for your page size.
Microsoft Windows 7
Chrome 19.0.1084.52
Screen Resolution:1366 x 768
Browser Size:1366 x 610