ZStack fix

druid/src/core.rs

@@ -666,12 +666,11 @@ impl<T: Data, W: Widget<T>> WidgetPod<T, W> {
         }
 
         // TODO: factor as much logic as possible into monomorphic functions.
-        if ctx.is_handled
-            && !matches!(
-                event,
-                Event::MouseDown(_) | Event::MouseUp(_) | Event::MouseMove(_) | Event::Wheel(_)
-            )
-        {
+        // a follow_up event should reach the widget which handled the first event.
+        // in this case we dont discard events when ctx.is_handled is set but just dont set our hot
+        // state to true
+        let follow_up_event = event.is_pointer_event() && self.state.has_active;
+        if ctx.is_handled && !follow_up_event {
             // This function is called by containers to propagate an event from
             // containers to children. Non-recurse events will be invoked directly
             // from other points in the library.

druid/src/event.rs

@@ -448,6 +448,16 @@ impl Event {
             | Event::Zoom(_) => false,
         }
     }
+
+    /// Returns true if the event involves a cursor.
+    ///
+    /// These events interact with the hot state and
+    pub fn is_pointer_event(&self) -> bool {
+        matches!(
+            self,
+            Event::MouseDown(_) | Event::MouseUp(_) | Event::MouseMove(_) | Event::Wheel(_)
+        )
+    }
 }
 
 impl LifeCycle {

druid/src/widget/z_stack.rs

@@ -1,6 +1,6 @@
 use crate::{
-    BoxConstraints, Data, Env, Event, EventCtx, LayoutCtx, LifeCycle, LifeCycleCtx, PaintCtx,
-    Point, Rect, Size, UnitPoint, UpdateCtx, Vec2, Widget, WidgetExt, WidgetPod,
+    BoxConstraints, Data, Env, Event, EventCtx, InternalEvent, LayoutCtx, LifeCycle, LifeCycleCtx,
+    PaintCtx, Point, Rect, Size, UnitPoint, UpdateCtx, Vec2, Widget, WidgetExt, WidgetPod,
 };
 
 /// A container that stacks its children on top of each other.
@@ -94,17 +94,22 @@ impl<T: Data> ZStack<T> {
 
 impl<T: Data> Widget<T> for ZStack<T> {
     fn event(&mut self, ctx: &mut EventCtx, event: &Event, data: &mut T, env: &Env) {
-        let is_pointer_event = matches!(
-            event,
-            Event::MouseDown(_) | Event::MouseMove(_) | Event::MouseUp(_) | Event::Wheel(_)
-        );
-
+        let mut previous_hot = false;
         for layer in self.layers.iter_mut() {
-            layer.child.event(ctx, event, data, env);
-
-            if is_pointer_event && layer.child.is_hot() {
-                ctx.set_handled();
+            if event.is_pointer_event() && previous_hot {
+                if layer.child.is_active() {
+                    ctx.set_handled();
+                    layer.child.event(ctx, event, data, env);
+                } else {
+                    layer
+                        .child
+                        .event(ctx, &Event::Internal(InternalEvent::MouseLeave), data, env);
+                }
+            } else {
+                layer.child.event(ctx, event, data, env);
             }
+
+            previous_hot |= layer.child.is_hot();
         }
     }