fix drag and drop in the drive

www/common/drive-ui.js

@@ -1995,8 +1995,11 @@ define([
                     return f;
                 }).filter(Boolean);
                 // Continue only with the files
+                // if there are no files, fall through to other handlers
+                if (fileDrop.length) {
                     return void onFileDrop(fileDrop, ev);
                 }
+            }
 
             var oldPaths = JSON.parse(data).path;
             if (!oldPaths) { return; }