GITBOOK-872: change request with no subject merged in GitBook

Author: vchelaru

docs/gum-tool/upgrading/migrating-to-2026-march.md

@@ -52,3 +52,93 @@ else
 ```
 
 Code that only writes to the `Blend` property (setter) is not affected by this change.
+
+### \[Breaking] BindableGue Deprecated - Binding Moved to GraphicalUiElement
+
+Previous versions of Gum provided binding support (data context, `SetBinding`, `BindingContext`) through a separate class called `BindableGue`, which sat between `GraphicalUiElement` and `InteractiveGue` in the inheritance hierarchy. This functionality has been moved directly into `GraphicalUiElement`, making binding available on all Gum runtime objects without requiring a specific base class.
+
+The `BindableGue` class still exists and compiles, but it is now marked `[Obsolete]` and is simply a subclass of `GraphicalUiElement` with no additional functionality. It will be removed in a future version.
+
+The following changes may be required depending on how your project uses `BindableGue`.
+
+#### How to Update
+
+Most projects will see compiler warnings on any code that references `BindableGue` by name. The fix in all cases is to replace `BindableGue` with `GraphicalUiElement`.
+
+**Custom classes that inherit BindableGue**
+
+If you have custom runtime classes that inherit from `BindableGue`, change the base class to `GraphicalUiElement`.
+
+❌ Old:
+
+```csharp
+public class MyCustomRuntime : BindableGue
+{
+    // ...
+}
+```
+
+✅ New:
+
+```csharp
+public class MyCustomRuntime : GraphicalUiElement
+{
+    // ...
+}
+```
+
+**Variables typed as BindableGue**
+
+If you store runtime references in variables typed as `BindableGue`, change the type to `GraphicalUiElement`.
+
+❌ Old:
+
+```csharp
+BindableGue currentScreen;
+```
+
+✅ New:
+
+```csharp
+GraphicalUiElement currentScreen;
+```
+
+**SkiaGum Children collection and related methods**
+
+The `Children` collection and child management methods on `GumSKElement` (SkiaGum WPF) and `SkiaGumCanvasView` (SkiaGum MAUI) previously used `BindableGue` as their element type. These now use `GraphicalUiElement`.
+
+❌ Old:
+
+```csharp
+ObservableCollection<BindableGue> children = myGumSKElement.Children;
+mySkiaCanvas.AddChild(myBindableGue);
+mySkiaCanvas.RemoveChild(myBindableGue);
+```
+
+✅ New:
+
+```csharp
+ObservableCollection<GraphicalUiElement> children = myGumSKElement.Children;
+mySkiaCanvas.AddChild(myGraphicalUiElement);
+mySkiaCanvas.RemoveChild(myGraphicalUiElement);
+```
+
+Since all existing `BindableGue` instances are also `GraphicalUiElement` instances, passing them to these methods continues to work without any casting.
+
+#### Codegen Output
+
+The Gum tool's code generation previously produced classes that inherit from `Gum.Wireframe.BindableGue`. Regenerating your runtime classes with the updated Gum tool will produce classes that inherit from `Gum.Wireframe.GraphicalUiElement` instead.
+
+❌ Old (generated):
+
+```csharp
+public partial class MyScreenRuntime : Gum.Wireframe.BindableGue
+```
+
+✅ New (generated):
+
+```csharp
+public partial class MyScreenRuntime : Gum.Wireframe.GraphicalUiElement
+```
+
+Existing generated files that still reference `Gum.Wireframe.BindableGue` will continue to compile during the deprecation period since `BindableGue` still exists. However, regenerating the files is recommended to avoid deprecation warnings and to prepare for the eventual removal of `BindableGue`.