TextBox, PropertyChangeHandler

src/Library/TerminalUI/FocusManager.cs

@@ -0,0 +1,31 @@
+using TerminalUI.Traits;
+
+namespace TerminalUI;
+
+public class FocusManager : IFocusManager
+{
+    private IFocusable? _focused;
+
+    public IFocusable? Focused
+    {
+        get
+        {
+            if (_focused is not null && !_focused.IsVisible)
+            {
+                _focused = null;
+            }
+
+            return _focused;
+        }
+
+        private set => _focused = value;
+    }
+
+    public void SetFocus(IFocusable focusable) => Focused = focusable;
+
+    public void UnFocus(IFocusable focusable)
+    {
+        if (Focused == focusable)
+            Focused = null;
+    }
+}