Internet Exporer 8: An interesting process handling and Memory consumption behaviour

I and Rejin were testing Internet Explorer 8 when we found this interesting behaviour. I decided to dig it a bit further..

My observations below...

Observation 1:
Opened up an Explorer window, the task manager has shown me  two instances of iexplore.exe running.  I understand this is by design and could  be attributed to the loosely coupled architecuture which enables Internet Explorer 8 to have features like crash recovery.




Observation 2:

Opened up a new tab in the existing window. The number of iexplore.exe processes in the taskmanager becomes 3.
This again is by design. This ensures that once tab if hung will not make other sessions hang.





Observation 3:

This is the most interesting part of it. When I closed down the tab that I just opened, the number of iexplore.exe process ilsted in Task Manager  did not change. It remained at 3. I couldnt believe that such a straight forward memory leak is possible for a tested product like IE 8.





I decided to test this further, opened up 4 more tabs, ensured that 5 iexplore.exe processes were listed in task manager. Then next thing I did was to close down all the additional tabs, and then I proceeded for a 5 minutes coffee break.

Surprisingly enough, when I came back and looked at the Task Manager window,  the number of iexplore.exe processes listed were only 2.  My initial impression was right, a product like IE8 can not have a bug as  straight forward as this.

During the next trial, I turned on the stop-watch and closely observed the additional iexplore.exe processes disappearing timing.. Interesting enough.. it had a pattern... 

The additional iexplore.exe's were dying down after 60 seconds of closing the correspoding tabs. I guess this also has to do something with the session recovery and to the new design..( not really sure)..