The problem you’ve outlined is very likely caused by an outdated version of jQuery library you use in your control panel. A recommended jQuery version is 1.6.1 or higher. To fix this issue, follow these steps:
1. Download and unzip the most up-to-date version of JQuery
1. Go to the following folder on your server /themes/javascript/compressed/jquery/
2. Backup the old jquery.js file located in this folder
3. Replace the old jquery.js file with the new one recently downloaded
Once these steps are completed, you should be good to go.