Dear Ata,
1. upload button is disabled for 5 seconds. It can be clicked 5 seconds after the page is loaded.
A: When the page is loaded, the uploader need load 100K script. After the script runs,the script will disable the button, and load the Flash or Silverlight.
If Flash/Silverlight can't be loaded by an unknown reason, the script will choose IFrame mode when the addon is not loaded within 5 seconds. This is a normal behavior.
2. we used to multi-select files. but at the moment we cannot.
A:The feature of Selecting Multiple files Upload needs Flash or Silverlight installed. Otherwise it will use an Iframe solution which allows you upload multiple files but selecting one file only.Please check whether you installed Silverlight or Flash.
Thank you for asking