Put a 'console.log(new Date());' entry inside of the auto-draft 
function (don't have access to the code right this second, so not sure 
of the official function name) in js/compose-dimp.js.

Do note that drafts will NOT be auto-saved unless something has 
actually changed in the timespan since the last update.  Maybe that's 
why you are not seeing consistent updates.

Can you give me a patch/info to monitor or so...?
I just watched several times with different auto_save settings (1min, 
5min) the draft folder on the imap server (watch -n 1 ls...) directly.

Can't reproduce.

Added console log to the code - logging when the periodical executor 
is defined, and then every time the save drafts it is run.  Used a 5 
second interval for testing.

// Initial definition
Date {Wed Apr 16 2014 14:44:29 GMT-0600 (Mountain Standard Time)}
compos...1884070 (line 685)
// First run (to init the hash values)
Date {Wed Apr 16 2014 14:44:29 GMT-0600 (Mountain Standard Time)}
compos...1884070 (line 705)
// Second run
Date {Wed Apr 16 2014 14:44:34 GMT-0600 (Mountain Standard Time)}
compos...1884070 (line 705)
// Third run
Date {Wed Apr 16 2014 14:44:39 GMT-0600 (Mountain Standard Time)}
compos...1884070 (line 705)
[etc...]

It's correctly being run every X seconds (X in the test = 5 seconds).

- tested with chrome and ff latest
- in dynamic view
- with "Compose message in a seperate window"

The preset time of auto_save_drafts is exactly the double for the 
first save. So the 5min auto save tasks will be done after now+10, 
now+15, now+20...

realy a minor bug... casually found...