Remove Core prefix from remaining UI widget components (#23938)

# Objective

This prefix was ruled unhelpful, and we previously removed it from most
of our types.

We missed a few apparently (spotted in #23924).

## Solution

Find and replace + update the migration guide.

_release-content/migration-guides/Core-Prefix-Removal.md

@@ -0,0 +1,12 @@
+---
+title: "`Core` prefix removed from UI widget components"
+pull_requests: [23612, 23938]
+---
+
+`CoreScrollbarThumb` has been renamed to `ScrollbarThumb`.
+`CoreScrollbarDragState` has been renamed to `ScrollbarDragState`.
+`CoreSliderDragState` has been renamed to `SliderDragState`.
+
+Additionally, `ScrollbarThumb` nodes are now laid out after `ui_layout_system` by `update_scrollbar_thumb`. `ScrollbarThumb` entities do
+not have a `Node` component. The only layout options are for borders, which can be set using `ScrollbarThumb`'s new
+`border` and `border_radius` fields.

_release-content/migration-guides/CoreScrollThumb-is-now-ScrollThumb.md

@@ -1,10 +0,0 @@
----
-title: "CoreScrollbarThumb is now `ScrollbarThumb` and scroll bar thumb layout is updated separately"
-pull_requests: [23612]
----
-
-`CoreScrollbarThumb` has been renamed to `ScrollbarThumb`.
-
-`ScrollbarThumb` nodes are now laid out after `ui_layout_system` by `update_scrollbar_thumb`. `ScrollbarThumb` entities do
-not have a `Node` component. The only layout options are for borders, which can be set using `ScrollbarThumb`'s new
-`border` and `border_radius` fields.

crates/bevy_ui_widgets/src/scrollbar.rs

@@ -76,7 +76,7 @@ pub struct Scrollbar {
 /// size and scroll position.
 #[derive(Component, FromTemplate, Debug, Default)]
 #[require(
-    CoreScrollbarDragState,
+    ScrollbarDragState,
     ComputedNode,
     ComputedUiTargetCamera,
     ComputedUiRenderTargetInfo,
@@ -119,7 +119,7 @@ impl Scrollbar {
 /// inserted on the thumb entity.
 #[derive(Component, Default, Reflect)]
 #[reflect(Component, Default)]
-pub struct CoreScrollbarDragState {
+pub struct ScrollbarDragState {
     /// Whether the scrollbar is currently being dragged.
     pub dragging: bool,
     /// The value of the scrollbar when dragging started.
@@ -187,7 +187,7 @@ fn scrollbar_on_pointer_down(
 
 fn scrollbar_on_drag_start(
     mut ev: On<Pointer<DragStart>>,
-    mut q_thumb: Query<(&ChildOf, &mut CoreScrollbarDragState), With<ScrollbarThumb>>,
+    mut q_thumb: Query<(&ChildOf, &mut ScrollbarDragState), With<ScrollbarThumb>>,
     q_scrollbar: Query<&Scrollbar>,
     q_scroll_area: Query<&ScrollPosition>,
 ) {
@@ -207,7 +207,7 @@ fn scrollbar_on_drag_start(
 
 fn scrollbar_on_drag(
     mut ev: On<Pointer<Drag>>,
-    mut q_thumb: Query<(&ChildOf, &mut CoreScrollbarDragState), With<ScrollbarThumb>>,
+    mut q_thumb: Query<(&ChildOf, &mut ScrollbarDragState), With<ScrollbarThumb>>,
     mut q_scrollbar: Query<(&ComputedNode, &Scrollbar)>,
     mut q_scroll_pos: Query<(&mut ScrollPosition, &ComputedNode), Without<Scrollbar>>,
     ui_scale: Res<UiScale>,
@@ -249,7 +249,7 @@ fn scrollbar_on_drag(
 
 fn scrollbar_on_drag_end(
     mut ev: On<Pointer<DragEnd>>,
-    mut q_thumb: Query<&mut CoreScrollbarDragState, With<ScrollbarThumb>>,
+    mut q_thumb: Query<&mut ScrollbarDragState, With<ScrollbarThumb>>,
 ) {
     if let Ok(mut drag) = q_thumb.get_mut(ev.entity) {
         ev.propagate(false);
@@ -261,7 +261,7 @@ fn scrollbar_on_drag_end(
 
 fn scrollbar_on_drag_cancel(
     mut ev: On<Pointer<Cancel>>,
-    mut q_thumb: Query<&mut CoreScrollbarDragState, With<ScrollbarThumb>>,
+    mut q_thumb: Query<&mut ScrollbarDragState, With<ScrollbarThumb>>,
 ) {
     if let Ok(mut drag) = q_thumb.get_mut(ev.entity) {
         ev.propagate(false);

crates/bevy_ui_widgets/src/slider.rs

@@ -96,7 +96,7 @@ pub enum TrackClick {
 #[derive(Component, FromTemplate, Debug, Default, Clone)]
 #[require(
     AccessibilityNode(accesskit::Node::new(Role::Slider)),
-    CoreSliderDragState,
+    SliderDragState,
     SliderValue,
     SliderRange,
     SliderStep
@@ -238,7 +238,7 @@ impl SliderPrecision {
 /// Component used to manage the state of a slider during dragging.
 #[derive(Component, Default, Reflect)]
 #[reflect(Component)]
-pub struct CoreSliderDragState {
+pub struct SliderDragState {
     /// Whether the slider is currently being dragged.
     pub dragging: bool,
 
@@ -362,11 +362,7 @@ pub(crate) fn slider_on_pointer_down(
 pub(crate) fn slider_on_drag_start(
     mut drag_start: On<Pointer<DragStart>>,
     mut q_slider: Query<
-        (
-            &SliderValue,
-            &mut CoreSliderDragState,
-            Has<InteractionDisabled>,
-        ),
+        (&SliderValue, &mut SliderDragState, Has<InteractionDisabled>),
         With<Slider>,
     >,
 ) {
@@ -388,7 +384,7 @@ pub(crate) fn slider_on_drag(
             &SliderRange,
             Option<&SliderPrecision>,
             &UiGlobalTransform,
-            &CoreSliderDragState,
+            &SliderDragState,
             Has<InteractionDisabled>,
         ),
         With<Slider>,
@@ -432,7 +428,7 @@ pub(crate) fn slider_on_drag_end(
             &SliderRange,
             Option<&SliderPrecision>,
             &UiGlobalTransform,
-            &mut CoreSliderDragState,
+            &mut SliderDragState,
             Has<InteractionDisabled>,
         ),
         With<Slider>,
@@ -478,7 +474,7 @@ fn emit_slider_drag_value_change(
     range: &SliderRange,
     precision: Option<&SliderPrecision>,
     transform: &UiGlobalTransform,
-    drag: &CoreSliderDragState,
+    drag: &SliderDragState,
     q_thumb: &Query<&ComputedNode, With<SliderThumb>>,
     q_children: &Query<&Children>,
     ui_scale: &UiScale,

examples/ui/scroll_and_overflow/scrollbars.rs

@@ -5,7 +5,7 @@ use bevy::{
     input_focus::tab_navigation::{TabGroup, TabNavigationPlugin},
     picking::hover::Hovered,
     prelude::*,
-    ui_widgets::{ControlOrientation, CoreScrollbarDragState, Scrollbar, ScrollbarThumb},
+    ui_widgets::{ControlOrientation, Scrollbar, ScrollbarDragState, ScrollbarThumb},
 };
 
 fn main() {
@@ -159,10 +159,10 @@ fn text_row(caption: &str) -> impl Bundle {
 // Update the color of the scrollbar thumb.
 fn update_scrollbar_thumb(
     mut q_thumb: Query<
-        (&mut BackgroundColor, &Hovered, &CoreScrollbarDragState),
+        (&mut BackgroundColor, &Hovered, &ScrollbarDragState),
         (
             With<ScrollbarThumb>,
-            Or<(Changed<Hovered>, Changed<CoreScrollbarDragState>)>,
+            Or<(Changed<Hovered>, Changed<ScrollbarDragState>)>,
         ),
     >,
 ) {

examples/ui/widgets/standard_widgets.rs

@@ -18,9 +18,9 @@ use bevy::{
     ui_widgets::{
         checkbox_self_update, observe,
         popover::{Popover, PopoverAlign, PopoverPlacement, PopoverSide},
-        Activate, Button, Checkbox, CoreSliderDragState, MenuAction, MenuButton, MenuEvent,
-        MenuItem, MenuPopup, RadioButton, RadioGroup, Slider, SliderRange, SliderThumb,
-        SliderValue, TrackClick, ValueChange,
+        Activate, Button, Checkbox, MenuAction, MenuButton, MenuEvent, MenuItem, MenuPopup,
+        RadioButton, RadioGroup, Slider, SliderDragState, SliderRange, SliderThumb, SliderValue,
+        TrackClick, ValueChange,
     },
 };
 
@@ -453,7 +453,7 @@ fn update_slider_style(
             &SliderValue,
             &SliderRange,
             &Hovered,
-            &CoreSliderDragState,
+            &SliderDragState,
             Has<InteractionDisabled>,
         ),
         (
@@ -461,7 +461,7 @@ fn update_slider_style(
                 Changed<SliderValue>,
                 Changed<SliderRange>,
                 Changed<Hovered>,
-                Changed<CoreSliderDragState>,
+                Changed<SliderDragState>,
                 Added<InteractionDisabled>,
             )>,
             With<DemoSlider>,
@@ -484,12 +484,7 @@ fn update_slider_style(
 
 fn update_slider_style2(
     sliders: Query<
-        (
-            Entity,
-            &Hovered,
-            &CoreSliderDragState,
-            Has<InteractionDisabled>,
-        ),
+        (Entity, &Hovered, &SliderDragState, Has<InteractionDisabled>),
         With<DemoSlider>,
     >,
     children: Query<&Children>,

examples/ui/widgets/vertical_slider.rs

@@ -5,7 +5,7 @@ use bevy::{
     picking::hover::Hovered,
     prelude::*,
     ui_widgets::{
-        observe, slider_self_update, CoreSliderDragState, Slider, SliderRange, SliderThumb,
+        observe, slider_self_update, Slider, SliderDragState, SliderRange, SliderThumb,
         SliderValue, TrackClick,
     },
 };
@@ -257,14 +257,14 @@ fn update_slider_visuals(
             &SliderValue,
             &SliderRange,
             &Hovered,
-            &CoreSliderDragState,
+            &SliderDragState,
             Has<VerticalSlider>,
         ),
         (
             Or<(
                 Changed<SliderValue>,
                 Changed<Hovered>,
-                Changed<CoreSliderDragState>,
+                Changed<SliderDragState>,
             )>,
             With<DemoSlider>,
         ),