Non-UCS-2 characters are not handled properly when deleting individual characters leaving a broken character on the first backspace input which then requires a second backspace press to delete.

Reproducible: Always

Steps to Reproduce:
1. Open a new (empty) document Kate / KWrite
2. Enter the FIRE character (U+1F525, see http://www.fileformat.info/info/unicode/char/1f525/index.htm under "Java Data")
3. Press backspace to delete the entered character
Actual Results:  
The FIRE character is replaced by a broken (empty box) character - someone didn't expect that UTF-16 != UCS-2?

Expected Results:  
The document is empty again.

This works correctly other text input fields in KDE.

Even in the kate part navigation via the arrow keys and selecting via the mouse properly recognizes U+1F525 as one single character.