See if the option "Remember and apply each folder's sorting mode separately" is enabled. It is located in Tools | Options | Incoming mail | Preview mode settings. I don't know whether this setting has any affect when in List mode but it affects sort mode so seems worth looking into.
Also, if you are running the main Pegasus Mail window maximized try restoring it down and then changing your sorting preference. Restart Pegasus Mail (while not maximized) and see if the sort option stuck.
<p>See if the option "Remember and apply each folder's sorting mode separately" is enabled.&nbsp; It is located in Tools | Options | Incoming mail | Preview mode settings.&nbsp; I don't know whether this setting has any affect when in List mode but it affects sort mode so seems worth looking into.
</p><p>Also, if you are running the main Pegasus Mail window maximized try restoring it down and then changing your sorting preference.&nbsp; Restart Pegasus Mail (while not maximized) and see if the sort option stuck.&nbsp;
</p>