String var returns null on OnWorkEnd after TldHTTP.Get (Indy 8)

I'm a newbie to both Delphi and Indy, so no offence if this is a dumb
question:

I'm using TldHTTP to write simple client that pulls a webpage. I don't need
any fancy stuff, and just want to use a simple string var for storing the
webpage. I did a StringVar := IDHTTP1.Get('http://www.yahoo.com')

I used the OnWorkEnd event to figure when to start parsing StringVar, but
all StringVar returns is it's initial value (null in this case).

After OnWorkEnd has been handled, any other routine (eg Form1.Click) shows
StringVar perfectly with the body of the webpage.

Also, calling the get procedure the second time and all subsequent times
also gives the proper StringVar val.

Any ideas why Get hasn't written its results to StringVar by the time
OnWorkEnd is called?

TIA,
Ishaan