Problem: some CKEditor textfields not showing in IE10

Hello all,

I have a problem within a project. This project uses CKEditor 4.1. Users that use IE10 don't see all CKEditor fields. Strangely enough, that only happens with a specific defined CKEditor field. My config.js looks as follows:

/**
 * @license Copyright (c) 2003-2012, CKSource - Frederico Knabben. All rights reserved.
 * For licensing, see LICENSE.html or http://ckeditor.com/license
 */

CKEDITOR.editorConfig = function( config )
{
    config.toolbar = 'BasicEditor';
    config.scayt_autoStartup = true;
    config.defaultLanguage = 'nl';
    config.scayt_defLan = 'nl';
    config.scayt_sLang = 'nl';
    config.autoParagraph = false;
    config.enterMode = CKEDITOR.ENTER_BR;
 
    config.toolbar_BasicEditor =
    [            
        { name: 'basicstyles', items : [ 'Bold','Italic','Underline','-','NumberedList','BulletedList','-','Link','Unlink','-','Maximize','-','SpellChecker', 'Scayt' ] }
    ];
    
    config.toolbar = 'Kolombeperkt';
 
    config.toolbar_Kolombeperkt =
    [            
        { name: 'basicstyles', items : [ 'Bold','Italic','Underline','TextColor','-','Undo','Redo','PasteFromWord','-','NumberedList','BulletedList','-','JustifyLeft','JustifyCenter','JustifyRight' ] },
        '/',
        { name: 'styles', items : [ 'SpellCheck','-','Link','Unlink','Image','-','RemoveFormat','Source','Table','Maximize','-','HorizontalRule','-','SpellChecker', 'Scayt' ] },
        '/',
        { name: 'fonts', items : [ 'Font','FontSize','Format','SpecialChar' ] }
    ];
    
    config.toolbar = 'Kolombeperkt_tweekolom';
 
    config.toolbar_Kolombeperkt_tweekolom =
    [            
        { name: 'basicstyles', items : [ 'Bold','Italic','Underline','TextColor','-','Undo','Redo','PasteFromWord','-','NumberedList','BulletedList','-','JustifyLeft','JustifyCenter','JustifyRight','-','Link','Unlink','Image','-','RemoveFormat','Table','-','HorizontalRule','-','SpellChecker', 'Scayt','SpecialChar' ] },
        '/',
        { name: 'styles', items : [ 'Font','FontSize','Format','Source','Maximize' ] },
    ];
    
    config.toolbar = 'Volledig';
 
    config.toolbar_Volledig =
    [            
        { name: 'document', items : [ 'Source','-','Save','NewPage','DocProps','Preview','Print','-','Templates' ] },
        { name: 'clipboard', items : [ 'Cut','Copy','Paste','PasteText','PasteFromWord','-','Undo','Redo' ] },
        { name: 'editing', items : [ 'Find','Replace','-','SelectAll','-','SpellChecker', 'Scayt' ] },
        { name: 'forms', items : [ 'Form', 'Checkbox', 'Radio', 'TextField', 'Textarea', 'Select', 'Button', 'ImageButton', 
            'HiddenField' ] },
        '/',
        { name: 'basicstyles', items : [ 'Bold','Italic','Underline','Strike','Subscript','Superscript','-','RemoveFormat' ] },
        { name: 'paragraph', items : [ 'NumberedList','BulletedList','-','Outdent','Indent','-','Blockquote','CreateDiv',
        '-','JustifyLeft','JustifyCenter','JustifyRight','JustifyBlock','-','BidiLtr','BidiRtl' ] },
        { name: 'links', items : [ 'Link','Unlink','Anchor' ] },
        { name: 'insert', items : [ 'Image','Flash','Table','HorizontalRule','Smiley','SpecialChar','PageBreak','Iframe' ] },
        '/',
        { name: 'styles', items : [ 'Styles','Format','Font','FontSize' ] },
        { name: 'colors', items : [ 'TextColor','BGColor' ] },
        { name: 'tools', items : [ 'Maximize', 'ShowBlocks','-','About' ] }
    ];
    
};

The problem only happens when I use the Kolombeperkt_tweekolom configuration. All the other work. I use the following code to make the Editor field appear:

<textarea id="ipa_content" name="ipa_content"></textarea>
                <script type="text/javascript">
                    CKEDITOR.replace( 'ipa_content',
                    {
                        toolbar : 'Kolombeperkt_tweekolom',
                        uiColor : '##e8e8e8',
                        height    : 450,
                    removePlugins     : 'elementspath'
                    });
                </script>

I hope someone can help me identify the problem.