Add custom editor for buttons that allow listening for them inside the editor.

Source/Editor/CustomEditors/Editors/MouseButtonEditor.cs

@@ -0,0 +1,37 @@
+using FlaxEngine;
+
+namespace FlaxEditor.CustomEditors.Editors
+{
+    /// <summary>
+    /// Custom editor for <see cref="MouseButton"/>.
+    /// Allows capturing mouse button presses and assigning them
+    /// to the edited value.
+    /// </summary>
+    [CustomEditor(typeof(MouseButton))]
+    public class MouseButtonEditor : BindableButtonEditor
+    {
+        /// <inheritdoc />
+        public override void Initialize(LayoutElementsContainer layout)
+        {
+            base.Initialize(layout);
+            Window.MouseUp += WindowOnMouseUp;
+        }
+
+        /// <inheritdoc />
+        protected override void Deinitialize()
+        {
+            Window.MouseUp -= WindowOnMouseUp;
+            base.Deinitialize();
+        }
+
+        private void WindowOnMouseUp(ref Float2 mouse, MouseButton button, ref bool handled)
+        {
+            if (!IsListeningForInput)
+                return;
+            IsListeningForInput = false;
+
+            SetValue(button);
+            handled = true;
+        }
+    }
+}