CKEDITOR in chrome adding "?" mark at cursor position while apply any style(bold/italic) without selection

CKEDITOR in chrome adding "?" mark at cursor position while apply any
style(bold/italic) without selection

I have a page which has CKEDITOR.when i try to apply any style(no
selection made just i clicked inside the editor) within the editor, it is
working in all other browser except chrome.
Chrome adding "?" mark at the cursor position.
is this ckeditor bug?
i try to find addCommand("bold")/addCommand("strong") function but its not
found
can i solve that issue?
Please help me out this issue.