When working with sass/scss, editing via source maps only works through the code editor in devtools.
However, any changes made in the elements -> styles tab are not saved to the sass/scss file.
For instance, if 'border-radius' is modified to a different value, it will not reflect in the scss file. https://i.sstatic.net/Sd9TF.png
Here's an example of my scss code:
.SiteBuilder .e-row__select {
position: relative;
&:after {
content: '';
}
select {
border-radius: 4px;
}
}