If you get a situation in a SharePoint 2013 document library where your New Document or Edit Document buttons seem to do nothing, check if you have the Google Toolbar installed.
In my case, ever though I stopped using the toolbar quite a while ago, it was still there. After disabling the toolbar, the document library buttons started behaving themselves again.
It’s possible the issue is to do with the popup blocked in the Google Toolbar, so if you have your heart set on keeping the toolbar, you may want to have a poke around those settings.
Hope that helps