diff --git a/core/src/layout/event.rs b/core/src/layout/event.rs
index 4a9939b..a7abdb0 100644
--- a/core/src/layout/event.rs
+++ b/core/src/layout/event.rs
@@ -1,4 +1,4 @@
-use std::{cell::RefCell, hash::Hash, rc::Rc};
+use std::{hash::Hash, rc::Rc};
 
 use crate::{
     layout::{Ui, UiModule, WidgetId, WidgetRef},
@@ -24,11 +24,11 @@ pub struct EventIdCtx<'a, Ctx, Data, W: ?Sized> {
     pub data: Data,
 }
 
-pub trait EventFn<Ctx, Data>: FnMut(EventCtx<Ctx, Data>) + 'static {}
-impl<F: FnMut(EventCtx<Ctx, Data>) + 'static, Ctx, Data> EventFn<Ctx, Data> for F {}
+pub trait EventFn<Ctx, Data>: Fn(EventCtx<Ctx, Data>) + 'static {}
+impl<F: Fn(EventCtx<Ctx, Data>) + 'static, Ctx, Data> EventFn<Ctx, Data> for F {}
 
-pub trait WidgetEventFn<Ctx, Data, W: ?Sized>: FnMut(EventIdCtx<Ctx, Data, W>) + 'static {}
-impl<F: FnMut(EventIdCtx<Ctx, Data, W>) + 'static, Ctx, Data, W: ?Sized> WidgetEventFn<Ctx, Data, W>
+pub trait WidgetEventFn<Ctx, Data, W: ?Sized>: Fn(EventIdCtx<Ctx, Data, W>) + 'static {}
+impl<F: Fn(EventIdCtx<Ctx, Data, W>) + 'static, Ctx, Data, W: ?Sized> WidgetEventFn<Ctx, Data, W>
     for F
 {
 }
@@ -50,13 +50,13 @@ impl Ui {
         &mut self,
         id: WidgetRef<W>,
         event: E,
-        mut f: impl WidgetEventFn<Ctx, E::Data, W>,
+        f: impl WidgetEventFn<Ctx, E::Data, W>,
     ) {
         self.data
             .modules
             .get_mut::<E::Module<Ctx>>()
             .register(id.id(), event, move |ctx| {
-                (&mut f)(EventIdCtx {
+                f(EventIdCtx {
                     widget: id,
                     ui: ctx.ui,
                     state: ctx.state,
@@ -84,7 +84,7 @@ pub trait EventModule<E: Event, Ctx>: UiModule + Default {
     ) -> Option<impl FnOnce(EventCtx<Ctx, E::Data>) + use<'a, Self, Ctx, E>>;
 }
 
-type EventFnMap<Ctx, Data> = HashMap<WidgetId, Vec<Rc<RefCell<dyn EventFn<Ctx, Data>>>>>;
+type EventFnMap<Ctx, Data> = HashMap<WidgetId, Vec<Rc<dyn EventFn<Ctx, Data>>>>;
 pub struct DefaultEventModule<E: Event, Ctx> {
     map: HashMap<E, EventFnMap<Ctx, <E as Event>::Data>>,
 }
@@ -107,7 +107,7 @@ impl<E: HashableEvent, Ctx: 'static> EventModule<E, Ctx> for DefaultEventModule<
             .or_default()
             .entry(id)
             .or_default()
-            .push(Rc::new(RefCell::new(f)));
+            .push(Rc::new(f));
     }
 
     fn run<'a>(
@@ -121,7 +121,7 @@ impl<E: HashableEvent, Ctx: 'static> EventModule<E, Ctx> for DefaultEventModule<
             let fs = fs.clone();
             Some(move |ctx: EventCtx<Ctx, <E as Event>::Data>| {
                 for f in fs {
-                    f.borrow_mut()(EventCtx {
+                    f(EventCtx {
                         ui: ctx.ui,
                         state: ctx.state,
                         data: ctx.data.clone(),
@@ -143,7 +143,7 @@ impl<E: HashableEvent, Ctx: 'static> DefaultEventModule<E, Ctx> {
             for fs in map.values() {
                 let fs = fs.clone();
                 for f in fs {
-                    f.borrow_mut()(EventCtx {
+                    f(EventCtx {
                         ui: ctx.ui,
                         state: ctx.state,
                         data: ctx.data.clone(),
diff --git a/core/src/layout/ui.rs b/core/src/layout/ui.rs
index 67d89bc..09ca882 100644
--- a/core/src/layout/ui.rs
+++ b/core/src/layout/ui.rs
@@ -2,7 +2,7 @@ use image::DynamicImage;
 
 use crate::{
     layout::{
-        IdLike, PainterData, PixelRegion, TextureHandle, Vec2, Widget, WidgetHandle, WidgetId,
+        IdLike, PainterData, PixelRegion, TextureHandle, Vec2, WidgetHandle, WidgetId,
         WidgetInstance, WidgetLike, WidgetUpdate,
     },
     util::HashSet,
diff --git a/src/default/mod.rs b/src/default/mod.rs
index 31eae5d..db00ca2 100644
--- a/src/default/mod.rs
+++ b/src/default/mod.rs
@@ -91,7 +91,7 @@ impl<State: DefaultAppState> AppState for DefaultState<State> {
 
         let input_changed = ui_state.input.event(&event);
         let cursor_state = ui_state.cursor_state().clone();
-        let old = ui_state.focus.clone();
+        let old = ui_state.focus;
         if cursor_state.buttons.left.is_start() {
             ui_state.focus = None;
         }
diff --git a/src/widget/sense.rs b/src/widget/sense.rs
index 27b3953..f687f91 100644
--- a/src/widget/sense.rs
+++ b/src/widget/sense.rs
@@ -3,7 +3,6 @@ use crate::{
     layout::{UiModule, UiRegion, Vec2},
     util::HashMap,
 };
-use std::cell::RefCell;
 use std::{
     ops::{BitOr, Deref, DerefMut},
     rc::Rc,
@@ -98,7 +97,7 @@ pub enum ActivationState {
 /// but I'm not sure how or if worth it
 pub struct Sensor<Ctx, Data> {
     pub senses: CursorSenses,
-    pub f: Rc<RefCell<dyn EventFn<Ctx, Data>>>,
+    pub f: Rc<dyn EventFn<Ctx, Data>>,
 }
 
 pub type SensorMap<Ctx, Data> = HashMap<WidgetId, SensorGroup<Ctx, Data>>;
@@ -208,7 +207,7 @@ impl<Ctx: 'static> CursorModule<Ctx> {
                             scroll_delta: cursor.scroll_delta,
                             sense,
                         };
-                        (sensor.f.borrow_mut())(EventCtx {
+                        (sensor.f)(EventCtx {
                             ui,
                             state: ctx,
                             data,
@@ -309,7 +308,7 @@ impl<E: Event<Data = <CursorSenses as Event>::Data> + Into<CursorSenses>, Ctx: '
         // TODO: does not add to active if currently active
         self.map.entry(id).or_default().sensors.push(Sensor {
             senses: senses.into(),
-            f: Rc::new(RefCell::new(f)),
+            f: Rc::new(f),
         });
     }
 
@@ -333,7 +332,7 @@ impl<E: Event<Data = <CursorSenses as Event>::Data> + Into<CursorSenses>, Ctx: '
                 .collect();
             Some(move |ctx: EventCtx<Ctx, CursorData>| {
                 for f in fs {
-                    f.borrow_mut()(EventCtx {
+                    f(EventCtx {
                         state: ctx.state,
                         ui: ctx.ui,
                         data: ctx.data.clone(),