I'm using Lubuntu 11.04, after a fresh installation:

1) I login with a new (never used before) user
2) I click on the systemtray icon of the default network manager (I suppose it's nm-applet)
3) I select a line which in english might be "connect to a hidden wireless network" (I'm using a localized version, so it might be slighty different)
4) a popup is shown in which I enter the "network name", I choose "wpa & wpa2 personal" as "security wireless" and I enter the network password (these two last settings of course are correctly set according to my lan settings)
5) After a while after pressing the button "connect" the system freezes, only the mouse pointer can be moved but nothing can be clicked and everything stops working.
The only way out is an hard reset by pressing continuously the power button.
6) After rebooting and logging in with the same user as before everything works correctly again and it can connect to the wireless lan.

This behaviour can be seen on any new added user.

Does anyone else get this?
Is this a bug?

Many thanks in advance