added column helper and fixed some more bugs

Demos/UiDemo.cs

@@ -160,11 +160,19 @@ namespace Demos {
             root.AddChild(ElementHelper.NumberField(Anchor.AutoLeft, new Vector2(1, 10))).PositionOffset = new Vector2(0, 1);
 
             root.AddChild(new Paragraph(Anchor.AutoLeft, 1, "There is an easy helper method to make any amount of same-sized columns:") {PositionOffset = new Vector2(0, 1)});
-            var cols = ElementHelper.MakeColumns(root, new Vector2(1), 3);
+            var cols = ElementHelper.MakeColumns(root, Anchor.AutoLeft, new Vector2(1), 3);
             cols[0].AddChild(new Paragraph(Anchor.AutoLeft, 1, "This is the first column"));
             cols[1].AddChild(new Paragraph(Anchor.AutoLeft, 1, "This is the second column"));
             cols[2].AddChild(new Paragraph(Anchor.AutoLeft, 1, "This is the third column"));
 
+            root.AddChild(new Button(Anchor.AutoLeft, new Vector2(1, 10), "Show Info Box") {
+                OnClicked = (element, button) => {
+                    if (button == MouseButton.Left)
+                        ElementHelper.ShowInfoBox(this.UiSystem, Anchor.Center, 100, "This is an easy info box that you can open with just one line of code! It automatically closes when you press the button below as well.");
+                },
+                PositionOffset = new Vector2(0, 1)
+            });
+
             // Below are some querying examples that help you find certain elements easily
 
             var children = root.GetChildren();

MLEM.Ui/Elements/Element.cs

@@ -296,7 +296,7 @@ namespace MLEM.Ui.Elements {
                 child.ForceUpdateArea();
 
             if (this.SetHeightBasedOnChildren && this.Children.Count > 0) {
-                var lowest = this.GetLowestReachingChild();
+                var lowest = this.GetLowestReachingChild(false, true);
                 var newHeight = (lowest.area.Bottom - pos.Y + this.ScaledChildPadding.Y) / this.Scale;
                 if (newHeight != this.size.Y) {
                     this.size.Y = newHeight;
@@ -316,12 +316,12 @@ namespace MLEM.Ui.Elements {
             return this.Area;
         }
 
-        public Element GetLowestReachingChild() {
+        public Element GetLowestReachingChild(bool hiddenAlso, bool unattachableAlso) {
             Element lowest = null;
             // the lowest child is expected to be towards the back, so search is usually faster if done backwards
             for (var i = this.Children.Count - 1; i >= 0; i--) {
                 var child = this.Children[i];
-                if (child.isHidden)
+                if (!hiddenAlso && child.IsHidden || !unattachableAlso && !child.CanAutoAnchorsAttach)
                     continue;
                 if (child.Anchor > Anchor.TopRight && child.Anchor < Anchor.AutoLeft)
                     continue;
@@ -337,9 +337,7 @@ namespace MLEM.Ui.Elements {
 
             Element lastChild = null;
             foreach (var child in this.Parent.Children) {
-                if (!hiddenAlso && child.IsHidden)
+                if (!hiddenAlso && child.IsHidden || !unattachableAlso && !child.CanAutoAnchorsAttach)
-                    continue;
-                if (!unattachableAlso && !child.CanAutoAnchorsAttach)
                     continue;
                 if (child == this)
                     break;

MLEM.Ui/Elements/ElementHelper.cs

@@ -4,13 +4,29 @@ using MLEM.Input;
 namespace MLEM.Ui.Elements {
     public static class ElementHelper {
 
-        public static Group[] MakeColumns(Element parent, Vector2 totalSize, int amount, bool setHeightBasedOnChildren = true) {
+        public static Panel ShowInfoBox(UiSystem system, Anchor anchor, float width, string text, float buttonHeight = 10, string okText = "Okay") {
+            var box = new Panel(anchor, new Vector2(width, 1), Vector2.Zero, true);
+            box.AddChild(new Paragraph(Anchor.AutoLeft, 1, text));
+            box.AddChild(new Button(Anchor.AutoCenter, new Vector2(0.5F, buttonHeight), okText) {
+                OnClicked = (element, button) => {
+                    if (button == MouseButton.Left)
+                        system.Remove("InfoBox");
+                },
+                PositionOffset = new Vector2(0, 1)
+            });
+            system.Add("InfoBox", box);
+            return box;
+        }
+
+        public static Group[] MakeColumns(Element parent, Anchor anchor, Vector2 totalSize, int amount, bool setHeightBasedOnChildren = true) {
+            var group = new Group(anchor, totalSize, setHeightBasedOnChildren);
             var cols = new Group[amount];
             for (var i = 0; i < amount; i++) {
                 cols[i] = new Group(Anchor.AutoInline, new Vector2(totalSize.X / amount, totalSize.Y), setHeightBasedOnChildren);
-                if (parent != null)
+                group.AddChild(cols[i]);
-                    parent.AddChild(cols[i]);
             }
+            if (parent != null)
+                parent.AddChild(group);
             return cols;
         }
 

MLEM.Ui/Elements/Panel.cs

@@ -65,7 +65,7 @@ namespace MLEM.Ui.Elements {
                     return;
                 // the "real" first child is the scroll bar, which we want to ignore
                 var firstChild = this.Children[1];
-                var lowestChild = this.GetLowestReachingChild();
+                var lowestChild = this.GetLowestReachingChild(false, true);
                 // the max value of the scrollbar is the amount of non-scaled pixels taken up by overflowing components
                 var childrenHeight = lowestChild.Area.Bottom - firstChild.Area.Top;
                 this.ScrollBar.MaxValue = (childrenHeight - this.Area.Height) / this.Scale + this.ChildPadding.Y * 2;

MLEM.Ui/UiSystem.cs

@@ -120,18 +120,18 @@ namespace MLEM.Ui {
 
         public RootElement Add(string name, Element element) {
             var root = new RootElement(name, element, this);
-            this.Add(root);
+            return !this.Add(root) ? null : root;
-            return root;
         }
 
-        internal void Add(RootElement root, int index = -1) {
+        internal bool Add(RootElement root, int index = -1) {
             if (this.IndexOf(root.Name) >= 0)
-                throw new ArgumentException($"There is already a root element with name {root.Name}");
+                return false;
             if (index < 0 || index > this.rootElements.Count)
                 index = this.rootElements.Count;
             this.rootElements.Insert(index, root);
             root.Element.PropagateRoot(root);
             root.Element.PropagateUiSystem(this);
+            return true;
         }
 
         public void Remove(string name) {
@@ -153,8 +153,8 @@ namespace MLEM.Ui {
         }
 
         private Element GetMousedElement() {
-            foreach (var root in this.rootElements) {
+            for (var i = this.rootElements.Count - 1; i >= 0; i--) {
-                var moused = root.Element.GetMousedElement();
+                var moused = this.rootElements[i].Element.GetMousedElement();
                 if (moused != null)
                     return moused;
             }