internet explorer 9 bug with insert media

Hello,

first of all thank you for the great plugin. It worked for me without any problems for 2 years 🙂
One thing I detected today I would like to share with you.
In internet explorer 9, when I try to insert a media file to a post the wordpress standard popup where you can select and upload a media file shows at the bottom of the site an not as a pop up.
When I remove the plugin everything works fine.
Do you know something about this problem?
Wordpress version: 4.0.1
Plugin version: 3.9.3

Thank you,
Ivaylo

https://wordpress.org/plugins/extended-categories-widget/