User settings are specific to the user, so they wouldn’t get saved back to the .exe.config file, which is system wide.
From the docs of LocalSettingsProvider
:
Application-scoped settings and the
default user-scoped settings are
stored in a file named
application.exe.config, which is
created in the same directory as the
executable file. Application
configuration settings are read-only.
Specific user data is stored in a file
namedusername.config
, stored under
the user’s home directory.
So for a UserSettingsTest application just run from VS under the debugger (hence the vshost bit) I ended up with a path of:
C:\Users\Jon\AppData\Local\UserSettingsTest
\UserSettingsTest.vshost.e_Url_pdqoppugkz1vaawbhwkkcu5ibxpi2fgu
\1.0.0.0\user.config