62db5789_Known_Issues__Affected_Users
[Current Issue] Drag and drop: Dragging and dropping files into Moodle does not work in IE, Firefox v 3.6 and Safari v 5 and lower. [Status] This issue is currently with Moodle HQ. [Affected Users] 
Students, teaching staff and Moodle administrators Drag and drop for files is unavailable on some browsers (mostly Internet Explorer and older versions of Firefox and Safari). Instead use the ‘Add’ and upload file function. Alternatively, use another browser such as the most recent version of Firefox, Chrome or Safari.
Known Issues
Affected Users