Please describe the problem:
If you open and modify several files, the time between the auto-save popup dialog decreases. It seems like each "open of a file" installes its own watch-timer, which is never canceled.

Steps to reproduce:
1. Set the auto-save-time in Preferences->General->Auto-save time interval to 2 minutes
2. Open one file and make some modification, wait one minute, save the file. Write down the wall-clock-time as $tA.
3. open another file and make some modification. Write down the wall-clock-time as $tB.
4. wait for the auto-save dialog, canel that occurance. Write down the wall-clock-time as $tC.
5. wait for the second auto-save dialog.  Write down the wall-clock-time as $tD.

Actual results:
You get the auto-save dialog more often than 2 minutes, namely at $tC=$tA+i*2 and at $tD=$tB+i*2

Expected results:
The auto-save dialog should appear exactly 2 minutes appart.

Does this happen every time?
yes

Other information:
You can repeat the step 3 multiple times and each time another watchdog gets installed. Than you're constantly spammed with auto-save popup dialogs.