You can change any configuration values during execution and
those values will be valid for as long as the application is
running. However unless you call this method your changes will be
not be saved to the configuration file.
When setAsDefaultSettings is set to true, the registry
"DefaultSettings" entry will point to this configuration file.
Therefore by calling this method you can alter the configuration
values of any ImageGlue instance that runs on the machine. You can
use IGSettings.exe to achieve this, so normally you should not need
to call this method.
Depending on how you created this XConfig object, you may not be
able to save its settings as some configurations may be
Furthermore, this method will fail if some other process has
modified the configuration file in the meantime.