add doc comment regarding opacity support on X11
@@ -323,7 +323,9 @@ impl DoubleWindow {
unsafe { Fl_Double_Window_alpha(self.inner) }
}
- /// Set the window's alpha, u8::MAX is fully opaque. This should be called on a shown window
+ /// Set the window's alpha, u8::MAX is fully opaque.
+ /// This should be called on a shown window.
+ /// On X11, opacity support depends on the window manager.
pub fn set_alpha(&mut self, val: u8) {
assert!(!self.was_deleted());
assert!(self.shown());
