OK this relates to a very specific scenario and is not a bug. Checked it out with one of the MSFT TPC test managers. OK below will be the repro steps and then the workaround.

Scenario
Working on a wireless network with poor connectivity. Using TIP and in my scenario writing to hotmail. l lost a lot of data due to focus (cursor place) being thrown off by the network status notification popups. I didn't notice that the focus had left the mail reply so when I pressed Insert my text went off into the ether! btw if there is a means of resending/ redoing text entry let me know! I haven't discovered it so far.

Workaround
Simply switch off notifications. Bring up Network Connections Ul, there are multiple ways to do this. Go via Control Panel, or use your pen and stab it on network icon down by the system clock (ie where it says 4.26 PM). When UI is exposed, put focus (click once) on icon for the offending network connection. Bring up the properties, you can stab again or else pick it from the options on left hand side of the Ul. The correct option is "Change settings of this connection". A dialogue box should popup. It should default to General Tab. At the bottom of the box uncheck the option "Notify me when this connection has limited or no connectivity." Click ok. And you should be grand then.