When you click on a preset, the settings and the frequency programs if any, were both loaded in the past.
If you clicked on an Shell (Empty) Preset, it would wipe out any frequency programs that were loaded as its list of frequency programs is empty.
Say you had already assembled 3 hard to find frequency programs, and then realized you wanted to use the Killing (R) - JW preset, not the Killing (C) - JW preset.
In the past you would have to find all 3 of those frequency programs after switching which preset you were using.
Now you can uncheck Load Programs, and then switch the preset selection. It will only load the settings that go with that preset, preserving your already assembled frequency program list.
For more details, please check the link: