[xdebug-general] Tracing line by line

Hi, Derick!
First, I'd like to thank you for your excellent work! Xdebug really helps me
a lot :)
I've got a question:
Say I have the following code
<?php
$i = 10;
$i +=
    ++$i
    + $i
    + $i++;

print $i;
?>

How can I trace it line by line, i.e. I want to know how $i changes its
value from line 3 to 7, for now it's just 10 and 45 at one step. Is it
possible?
Thank you.

-- 
Regards,
Shein Alexey