source button appears twice in toolbar

Hi,

i´m using ckeditor 4, and i see that some pages show me 2 source buttons in the toolbar.

my config.js contains the follwoing:

CKEDITOR.editorConfig = function( config ) {
    config.toolbarGroups = [
        { name: 'clipboard',   groups: [ 'clipboard', 'undo' ] },
        { name: 'editing',     groups: [ 'find', 'selection', 'spellchecker' ] },
        { name: 'links' },
        { name: 'insert' },
        { name: 'forms' },
        { name: 'tools' },
        { name: 'document',       groups: [ 'mode', 'document', 'doctools' ] },
        { name: 'others' },
        '/',
        { name: 'basicstyles', groups: [ 'basicstyles', 'cleanup' ] },
        { name: 'paragraph',   groups: [ 'list', 'indent', 'blocks', 'align', 'bidi' ] },
        { name: 'styles' },
        { name: 'colors' },
        { name: 'about' }
    ];

config.removeButtons = 'Subscript,Superscript';

config.format_tags = 'p;h1;h2;h3;pre';

config.removeDialogTabs = 'image:advanced;link:advanced';

config.extraPlugins = 'moxiemanager,widget';
};

I think the problem is related to configuration since it only happens when I use CKEDITOR.replace("#textarea"), that is, in the case of CKEDITOR.inline("#textarea") I do see only one source button.

I will appreciate any hint that you can provide me.

Thanks in advance,

Paola