How to: Switch to Another Thread While Debugging
When you debug a multithreaded application, you can use any one of several methods to switch the context from the thread that you have been working with to another thread.
To switch to any thread that appears in the Threads window
Double-click the thread.
To switch to a thread in a source window
In the left gutter, right-click a thread indicator, point to Switch to, and then click the name of that thread to which you want to switch. The shortcut menu shows only the threads at that specific location.
If no indicators appear, right-click in the Threads window and verify that Show Threads in Source is selected.
To switch to a thread in the Debug Location toolbar
On the Debug Location toolbar, click the Thread box.
In the list, click the thread to which you want to switch.