You’ll have to update your Theme:
In the Theme, the Binder items and the Binder background can have separate colors.
Because the binder items indent, the background color appears on the left.
For the Binder background to match the Binder Items, make sure the background color in the Appearance Options for the Binder (used by the items!) is the same as the “Base” color in the Palette file of the Theme:
In ThemeName.pal, update:
Base(122,177,241) //LightBlue Binder BG!
Note that this may update other UI elements that use the Base color as well …
Alternatively, update the QSS Stylesheet to match the color of the QTreeView object to the background color (used by the items) in the Appearance Options for the Binder:
In ThemeName.QSS, update:
QTreeView::branch:selected:!active {
background: rgba(122,177,241,1); /light blue/
}
The reach the .pal Palette en .qss Stylesheet, rename the .scrtheme-file to *.zip and extract the four files of the Theme. To reload the Theme, zip the updated file(s) and rename the resulting zip to .scrtheme. Copy the Theme’s folder path en choose Window > Themes > Load Theme from file… Paste the path of the Theme’s folder and double-click the name of the Theme. Restart Scrivener to show the UI in the updated Theme.
Success!