IE is a breed apart. Yes it was one of the earlier browsers, but sadly uses a completely different 'Box Modal' than all the other browsers. You need to read about it by searching Google and you will be amased at what it can and cannot do. In some things like Fonts it was the only browser that used the sort of fonts that we have been wanting to use in Moodle for yeats. But that is another story.
IE can also go into Quirks Mode when something in a web page layout triggers it. This may be what is happening to your site. To cure this first make sure your own browser is not set to Compatibility Mode which in effect can swap from IE10 back to IE7 IE8 or IE9 compatibility. To do this got to View -> Compatibility settings and make sure your website URL is not listed there.
Next CLICK F12 (Function Key 12 which is top row of your keyboard). This should bring up a console that allows you to change from IE10 to IE9/8/7/Quirks mode. It is meant for Developers to use, but it is a good indicator to the user which tells you instantly what Mode it is running in.
As for Moodle Themes and IE10 there should be little difference, but if there is then odds on your browser is running in compatibility mode.
If none of this is relevant than you can file it as a BUG in Moodle Tracker under Moodle Ad-ons.