Appends the desktop theme toggle to a tab strip, once.
Guarded against duplicates: the tab strip is rebuilt whenever the registry changes, and a second toggle would both render twice and double-fire the theme change.
The tab strip element.
Appends the desktop theme toggle to a tab strip, once.
Guarded against duplicates: the tab strip is rebuilt whenever the registry changes, and a second toggle would both render twice and double-fire the theme change.