Version:            (using KDE 4.1.0)
OS:                Linux
Installed from:    Unlisted Binary Package

Try this:

echo -n "foo" > bar
kwrite bar

kwrite does not display the binary file warning, but it does not display any text either. The editor window is blank. You can type in it, but the text you type is invisible and if you click on the line, the cursor goes back to the beginning and it appears as if your text is gone.

If you then save the file, all the text you typed is prepended to the original line of text. If you reopen it, the same behaviour occurs (because the file still lacks a newline character).

On the console I see this:

QThreadStorage: Thread 0x8885908 exited after QThreadStorage 2147483645 destroyed

...but only after I exit kwrite, so it may not be related.