Restoring defaults, or renewing them after and update overwrites all options

[Seismix]

Bug Report

Description
The default settings currently overwrite all user options, whereas they should only overwrite CSS selector settings and leave other user options intact.

Steps to Reproduce

1. Apply custom settings for the extension, including both CSS selector settings and other options.
2. Reset to default settings.
3. Observe that all user options, not just the CSS selector settings, are overwritten.

Expected Behavior
The default settings should only overwrite CSS selector settings, while leaving other user-configured options unchanged.

Actual Behavior
The default settings overwrite all user options, including those that should remain unchanged.