Version:           4.3.4 (using KDE 4.3.4)
OS:                Linux
Installed from:    Gentoo Packages

1. Activate static word wrapping at column 80.

2. Type two times the same sentence:

"The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog."

(The last two words "lazy dog." should be in line 2 now.)

3. Place the cursor in front of the word "fox" in the second sentence.

4. Start typing "horse jumps over the lazy frog." and delete the remaining characters.

The result is:

"The quick brown fox jumps over the lazy dog. The quick brown horse jumps over
foxthe lazy frog."

This is wrong!

The correct result should be:

"The quick brown fox jumps over the lazy dog. The quick brown horse jumps over the lazy frog."

You can watch a video about that here (Flash plugin needed):

http://de.tinypic.com/usermedia.php?uo=t2QD%2BVcjymXg8lky0xnLFIh4l5k2TGxc