I'm getting the same issue in 4.6.0 and I don't have trim trailing spaces checked, either.
Switching to a new tab, using a code snippet, almost anything switches from real tabs mode back to spaces mode. If I open the *Program Settings* dialogue, the *Real Tabs* checkbox is still checked, and resaving the preference and returning to the editor resolves it for the current file, temporarily. It's driving me mad. -- <http://forum.pspad.com/read.php?2,66181,66439> PSPad freeware editor http://www.pspad.com
