The width discussions here pertain to the menu on the left of the toolbar. If you are setting breakpoints and using the Go button to run to them, the width you set on the breakpoints themselves affects what TotalView does. Breakpoints can be set to, when hit, stop just the one thread, all threads in the process to which the thread belongs, or all threads. If, for example, you have selected Thread width from the toolbar menu, but the breakpoint you are running to is set to stop all threads in the process (the default), then all threads in the process will be stopped instead of just the one thread as you might otherwise expect.

For a complete discussion of breakpoint widths, see Controlling an Action Point’s Width.