Version:           unspecified (using Devel) 
OS:                Linux

Subscribing to a share folder containing about 500 unread emails slows down the N900 so badly that tabs cannot be opened or closed anymore.

Reproducible: Always

Steps to Reproduce:
- Launch Kmail-mobile
- Click on your Imap account
- Open the 'Actions' tab
- Click on 'Account'
- Click on 'Edit account'
- Check the 'Enable Server-Side Subscriptions' check box
- Click on the 'Serverside subscription...' button and select a shared folder containing at least 500 unread emails
- Click on 'Ok' twice
- Reopen 'Actions' tab
- Click on 'Synchronize emails in account'

Actual Results:  
The N900 becomes so slow that it cannot perform simple operations like opening and closing tabs.

This last for more than 10 minutes.

It is a regression since I do not think this happened before.

Expected Results:  
This should not happen enabling the serverside subscription should not slow down the N900 so badly for so long.

N900, 4:4.6~20101117.1198109-1maemo1.1198084 

In a terminal using the 'top' command I got this information:
4202  4199 user     R    67500 27.4 43.6 /usr/bin/kmail-mobile --graphicssystem raster 
3400     1 user     S     7572  3.0 30.9 /usr/bin/strigidaemon 
4224  4206 user     S     7068  2.8  4.9 /usr/bin/akonadi_strigi_feeder --identifier akonadi_strigi_feeder