Cannot create two 'textColor' button in toolbar

[jianghongfei]

CKEditor version: 4.1.1 Browser: Chrome 27.0.1453.94 m Repro steps:

1. configure CKEditor like this:

   CKEDITOR.replace( 'editor1', {
   	toolbar: [['TextColor', 'TextColor' ]]
   } );
   

2. Click the second TextColor button

Desc:

this first button works fine, but error raised when click the second one.

I was trying to add textColor button in floating-tools, and got this error. I thought this is a bug of floating-tools at first, then I found two textColor button don't work on normal toolbar. I tried comboboxs like style, font, they work fine.