Cannot type double byte characters in Section through IE11

Summary

Users cannot type double byte characters (i.e. Japanese, Korean, Chinese) in Section in Confluence pages through IE11 (see the attached).

Environment

• IE11 (the problem did not happen in Firefox and Chrome)
• Microsoft IME (the problem did not happen in Google Japanese IME)

Steps to Reproduce

1. Install vanilla Confluence 5.8.8
2. Create a space and click "Create" button to create a page
3. In page edit mode, create a section in body field
4. Try to type double byte characters (i.e. Japanese, Korean, Chinese)

Expected Results

Users can type double byte characters. Specifically 'あ' will be shown when typing 'a' when using Japanese IME.

Actual Results

Users cannot type double byte characters. Specifically 'a' will be shown when typing 'a' even when using Japanese IME.

No exception is thrown in the atlassian-confluence.log file:

Notes

• Users cannot type double characters but they can copy&paste the characters

Workaround

• Use other browsers than IE11
• Use other IME than Microsoft IME (i.e. Google Japanese IME)