by Albert Wiersch » Tue Jan 08, 2013 9:04 am
Hello,
It is possible that it is making an automatic change.
When I did a test for this, I noticed it was automatically correcting DUal capitals. This could be the issue. You may want to disable that auto-correct option in the Spelling Options dialog.
Another possibility is that it is deleting trailing whitespace from one or more lines if your document contains a line (or more) that ends in whitespace. To make sure the problem isn't caused by this option, make sure the option to 'Leave Trailing Spaces' in the Editor Options (Editor->Other Editor page) is checked.

Albert Wiersch