Wrapped has_access in Option since it doesn't occur on all platforms. Similar to x11 fullscreen events..

src/lib.rs

@@ -18,7 +18,7 @@ pub struct Bounds {
 pub enum UnderlayEvent {
     Attach { 
         bounds: Bounds, 
-        has_access: bool,
+        has_access: Option<bool>,
         is_fullscreen: Option<bool>,
     },
     Detach,

src/linux/mod.rs

@@ -229,7 +229,7 @@ impl Runtime {
                 self.underlay_tx
                     .send(UnderlayEvent::Attach {
                         bounds,
-                        has_access: true,
+                        has_access: None,
                         is_fullscreen: Some(is_fullscreen),
                     })
                     .ok();

src/windows/mod.rs

@@ -373,7 +373,7 @@ impl Runtime {
 
         if let Some(bounds) = self.get_content_bounds() {
             self.underlay_tx
-                .send(UnderlayEvent::Attach { bounds, has_access, is_fullscreen: None })
+                .send(UnderlayEvent::Attach { bounds, has_access: Some(has_access), is_fullscreen: None })
                 .ok();
 
             self.target.is_focused = true;