From 4aff5a2875c9b3b1d947b143b846b5df55fed42d Mon Sep 17 00:00:00 2001
From: Ellpeck <me@ellpeck.de>
Date: Thu, 17 Mar 2022 20:36:30 +0100
Subject: [PATCH] Fixed RootElement.CanSelectContent returning incorrect
 results when CanBeSelected changes in children

---
 CHANGELOG.md          |  1 +
 MLEM.Ui/UiControls.cs |  6 +++---
 MLEM.Ui/UiSystem.cs   | 17 +----------------
 3 files changed, 5 insertions(+), 19 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e8c7a98..fb389ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,6 +61,7 @@ Fixes
 - Fixed UiControls allowing for non-selectable or non-mouseable elements to be marked as selected or moused
 - Fixed buttons and checkboxes changing their CanBeSelected and CanBePressed values when being disabled
 - Fixed children of Panel scroll bars also being scrolled
+- Fixed RootElement.CanSelectContent returning incorrect results when CanBeSelected changes in children
 
 Removals
 - Marked StyleProp equality members as obsolete
diff --git a/MLEM.Ui/UiControls.cs b/MLEM.Ui/UiControls.cs
index 697e7ac..69cd112 100644
--- a/MLEM.Ui/UiControls.cs
+++ b/MLEM.Ui/UiControls.cs
@@ -156,7 +156,7 @@ namespace MLEM.Ui {
         public virtual void Update() {
             if (this.IsInputOurs)
                 this.Input.Update();
-            this.ActiveRoot = this.System.GetRootElements().FirstOrDefault(root => root.CanSelectContent && !root.Element.IsHidden);
+            this.ActiveRoot = this.System.GetRootElements().FirstOrDefault(root => !root.Element.IsHidden && root.CanSelectContent);
 
             // MOUSE INPUT
             if (this.HandleMouse) {
@@ -274,7 +274,7 @@ namespace MLEM.Ui {
         /// <param name="element">The element to select, or null to deselect the selected element.</param>
         /// <param name="autoNav">Whether automatic navigation should be forced on</param>
         public void SelectElement(RootElement root, Element element, bool? autoNav = null) {
-            if (root == null || !root.CanSelectContent)
+            if (root == null)
                 return;
             if (element != null && !element.CanBeSelected)
                 return;
@@ -337,7 +337,7 @@ namespace MLEM.Ui {
         /// <param name="root">The root element whose selected element to return</param>
         /// <returns>The given root's selected element, or null if the root doesn't exist, or if there is no selected element for that root.</returns>
         public Element GetSelectedElement(RootElement root) {
-            if (root == null || !root.CanSelectContent)
+            if (root == null)
                 return null;
             this.selectedElements.TryGetValue(root.Name, out var element);
             if (element != null && !element.CanBeSelected)
diff --git a/MLEM.Ui/UiSystem.cs b/MLEM.Ui/UiSystem.cs
index 302f2da..d494dac 100644
--- a/MLEM.Ui/UiSystem.cs
+++ b/MLEM.Ui/UiSystem.cs
@@ -535,7 +535,7 @@ namespace MLEM.Ui {
         /// Determines whether this root element contains any children that <see cref="Elements.Element.CanBeSelected"/>.
         /// This value is automatically calculated.
         /// </summary>
-        public bool CanSelectContent { get; private set; }
+        public bool CanSelectContent => this.Element.CanBeSelected || this.Element.GetChildren(c => c.CanBeSelected, true).Any();
 
         /// <summary>
         /// Event that is invoked when a <see cref="Element"/> is added to this root element or any of its children.
@@ -558,21 +558,6 @@ namespace MLEM.Ui {
             this.Name = name;
             this.Element = element;
             this.System = system;
-
-            this.OnElementAdded += e => {
-                if (e.CanBeSelected)
-                    this.CanSelectContent = true;
-            };
-            this.OnElementRemoved += e => {
-                if (e.CanBeSelected) {
-                    // check if removing this element removed all other selectable elements
-                    foreach (var c in this.Element.GetChildren(regardGrandchildren: true)) {
-                        if (c.CanBeSelected)
-                            return;
-                    }
-                    this.CanSelectContent = false;
-                }
-            };
         }
 
         /// <summary>