The Worker thread is started at Desktop startup with the priority you specify here. This setting allows you to specify either "idle" priority with a priority delta of 0, or "idle" with a delta of +31, or "regular" priority with a delta of 0.
See "Processes and threads" for more information about thread priorities.
Note that this setting only specifies the default Worker thread priority. If &xwp; finds out that the Worker thread does not get enough processor time, its priority is raised automatically from time to time. See "Beep on priority change" for more.
For most purposes, you should leave this setting to the default value, which is "idle +31". This will allow the Worker thread to perform its tasks in the background without a noticeable slowdown of the user interface. However, if you frequently run processes which hog up your CPU (that is, if your CPU load is always 100% because of, e.g., certain Windows applications running), you might want to raise this to "regular".
You can examine the current Worker thread priority on the "Threads" page.