After anywhere from a couple minutes to 10+, all of the menus and buttons in the Google Docs/Drive apps stop responding. Meaning, clicking them results in no action. The document text and spreadsheet cells continue to be editable, but the menus, buttons on toolbars, and the GD right-click menu (not the browser native one) all stop responding. The only fix is to refresh the current page. This behavior is not present on the Apple released version of Safari (6.1.3). I can only assume this relates to Javascript, as these menus, buttons, and right-click menus are completely dependent on JS in order to work. I do a lot of work in Google Spreadsheets with large datasets connected to multiple files and sheets, so the behavior is one that frequently interrupts my workflow.