Japanese charactor disappeared while typing

[Chika Kato]

Steps to reproduce

1. In the editor demo (​http://ckeditor.com/demo#standard), click inside the window and performed a CTRL+A to select all text, and then hit the Delete key.
2. Once all data was deleted from that window, please select "Japanese" on the Windows language tool bar. Select the "Full-width Katakana" IME on the Windows language tool bar.
3. Go to inside the editor window and hit Enter to move to second line.
4. Hit the "A" key (あ） 30 times, and the cursor moved to the beginning of the line.
5. Hit the "A" key once more, and then all but two characters disappeared from that line.

Expected result

The cursor should not be moved to the beginning of the next line. If I hit "A" key 31 times, there should be 31 charactors appeard.

Actual result

When I hit the "A" key 30 times, the cursor moved to the beginning of the next line. If I hit the "A" key once more, and all but two characters disappeared from that line.

Other details (browser, OS, CKEditor version, installed plugins)

I could reproduce this with CKEditor 4.5

[Chika Kato]

The issue occurs only with IE11.

[Jakub Ś]

I was able to reproduce this issue starting from CKEditor 4.2 and only in IE11.

This enter from step 3 seems to be crucial to reproduce this issue.

[Chika Kato]

Replying to j.swiderski:

I was able to reproduce this issue starting from CKEditor 4.2 and only in IE11.

This enter from step 3 seems to be crucial to reproduce this issue.

Yes, as you pointed, the issue occurs only from second line or more.

[Jakub Ś]

Please don't change version. It is used to indicate when problem started occurring.

[Chika Kato]

I am not really sure when this problem started occurring. What I know is I could reproduce this with version 4.5.x.