In IE11 windows 8 call to window.localStorage was throwing out an access denied error. Using try and catch manages the issue and allows the script to execute in IE 11 in desktop mode.
I think it is a problem with IE11 rather than the way Silverstripe is implementing the preview via an iframe from what I have been reading. http://blogs.msdn.com/b/ieinternals/archive/2009/09/16/bugs-in-ie8-support-for-html5-postmessage-sessionstorage-and-localstorage.aspx. It seems that the way IE11 deals with localStorage is broken in certain cases but I am not 100% certain of the cause yet as I have not been able to find a definitive answer. I only noticed it was a problem when a new client said they couldn't view the admin screen properly in IE11. I took a look in IE11 and I was experiencing the same problem which makes the admin interface layout screw up and the preview doesn't work due the error mentioned in the first post.
Instead of the original code I submitted I have amended it and added an additional function to test more robustly to see if localStorage is available and can be accessed properly. It is a copy of the code on a blog post Mathias Bynens has written about detecting if localStorage is available and can be used: https://mathiasbynens.be/notes/localstorage-pattern
I have added a console.warn as you suggested if localStorage is not available so that at least you get a warning if localStorage tests fail.
I have tested this on Windows 8.1: Firefox, Chrome & Mac: Firefox, Safari, Chrome and it seems to work as expected. On IE11 it displays the admin area correctly now but obviously doesn't save the preview settings between page loads if localStorage is not available.
Convert namespaced class names to html safe strings in `LeftAndMain.php` `CMSMenu.php` and `LeftAndMain.Main.js` by replacing backslashes (\) with dashes (\) and removing special characters with `Convert::raw2htmlname()`
Code removed here intentonally prevented node selection when dragging but at the cost of clicks on site tree icons selecting the node but not loading the link. Since it's possible to drag a site tree item from the title, not just the icon, think it's better to remove this for now (choosing the lesser of two evils). A full fix to prevent node selection should follow, perhaps during an upgrade to jstree.
Export and print buttons are appearing outside the button row in model admin, meaning that if the add button is removed (say, by removing the create permission), the buttons are flush with the gridfield.
Same as with the import form - you can overload the public function `SearchForm` in your model admin subclass to not return a form and the title currently remains there which makes no sense.
