two issues i meet when using CKEditor 4.0.1

1, i'm load editor in dynamic code which generateed by ajax, for avoid repeat CKEDITOR.replace in one distance, i'm using

if (CKEDITOR.instances['name']){
     CKEDITOR.instances['name'].destroy();
};

it's ok when load next time CKEditor in one page, but there is a error occurred,

Uncaught TypeError: Cannot call method 'unselectable' of null

it's not serious cause the CKEditor could load successful.

2, i'm loading CKEditor in a floating layar depanding JQuery BlockUI, in CKEditor's every dialog window, like Link, Image, table, etc, every input column CAN NOT type, every drop menu CAN NOT appear then select, only work in dialog is Tab clicking to switch each page-in-dialog.

i tested the problems both in IE 10 and Chrome.

wish to fix them, thanks.