On IE7 (and IE6) sample application slowly leaks memory until it grinds the client to a halt. The issue can be reproduced with the attached simple example. Debugging with sIEve shows that the DOM tree and memory usage keeps increasing without ever garbage collecting.

Steps to reproduce:
1. Deploy attached .war on Tomcat 7 or Jboss 7.1 server
2. Start fresh IE 7 browser session (clear cache, cookies, temporary files etc)
3. Click tab 2, refresh.
4. Repeat 10 times
4. After 10 tab switches the memory consumption of IE7 process would increase up to 1 GB of RAM

Please note that minimization of the IE7 window will reset memory consumption to a reasonable value.
There also will be a non-resettable memory increase by about 10 Mb of RAM every time you restore IE7 window after steps 3 and 4 executed.
It is also worth to mention that when the BlockUIOnSubmit parameter is set to true, refreshes to the page cause a huge jump in memory consumption by IE7 process (~100 mb per single step 3 iteration in my test).