When you select this option, the entry is grayed out until you paste it into a new location using a Paste option.

The entry remains grayed in the window, but it is not used by RealView Debugger. It is restored if you Cut another entry.

If you delete the grayed entry, it is removed from the window and it is no longer available to paste.

If you want to disable a group, use the Disabled setting in the right pane.