To watch system variables
If the watch window is not visible, click Watches on the debugger View menu.
Click the arrow next to the New Watch
button on the toolbar.Choose System Variables from the drop-down list.
Click the checkboxes next to the System Variables you want to watch.
Click OK.
Tip
There are other convenience options on the New Watch drop-down list, such as IM2 vector.
Note
This is a convenience feature. You can also watch system variables by adding them like you would any other watch.