Cannot type double byte characters in page sections when using Microsoft IME through IE11

Summary

Users cannot type double byte characters (i.e. Japanese, Korean, Chinese) in Sections in Confluence pages when using the Microsoft IME through IE11 (see below).

Environment

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

Steps to Reproduce

1. Install a vanilla Confluence 5.8.8
2. Log in using Microsoft Internet Explorer 11 with Microsoft IME enabled
3. Create a space and click the "Create" button to create a page
4. In page edit mode, create a section in body field using the page editor controls
5. 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 exceptions are thrown in the atlassian-confluence.log file, or the browser error console.
 

Notes

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

Workarounds

• Use different a browser aside from IE11
• Use another IME aside from Microsoft's IME (i.e. Google Japanese IME)
• Instead of creating pages using page sections, use Section Macros. These are available on the macro browser.
• Create content outside of Confluence, then copy/paste into Confluence page sections