I've not seen this issue before, but since it seems limited to IE 11, have you tried IE Compatibility Mode?
In IE, go to the Tools menu and choose Compatibility View settings.
Next in the Compatibility View settings pop-up, you will need to add the URL for your adminui.
Ex. http://server.com:8080/iam/siteminder/adminui
I know we've had other IE issues with the UI resolved by this.
Hope this helps!