Add AE breaking change

docs/core/compatibility/3.1-5.0.md

@@ -41,12 +41,17 @@ If you're migrating from version 3.1 of .NET Core, ASP.NET Core, or EF Core to v
 ## Windows Forms
 
 - [Removed status bar controls](#removed-status-bar-controls)
-- [WinForms APIs now throw ArgumentNullException](#winforms-apis-now-throw-argumentnullexception)
+- [WinForms methods now throw ArgumentException](#winforms-methods-now-throw-argumentexception)
+- [WinForms methods now throw ArgumentNullException](#winforms-methods-now-throw-argumentnullexception)
 
 [!INCLUDE [winforms-deprecated-controls](../../../includes/core-changes/windowsforms/5.0/winforms-deprecated-controls.md)]
 
 ***
 
+[!INCLUDE [invalid-args-cause-argumentexception](../../../includes/core-changes/windowsforms/5.0/invalid-args-cause-argumentexception.md)]
+
+***
+
 [!INCLUDE [null-args-cause-argumentnullexception](../../../includes/core-changes/windowsforms/5.0/null-args-cause-argumentnullexception.md)]
 
 ***

docs/core/compatibility/winforms.md

@@ -12,7 +12,8 @@ The following breaking changes are documented on this page:
 | Breaking change | Version introduced |
 | - | :-: |
 | [Removed status bar controls](#removed-status-bar-controls) | 5.0 |
-| [WinForms APIs now throw ArgumentNullException](#winforms-apis-now-throw-argumentnullexception) | 5.0 |
+| [WinForms methods now throw ArgumentException](#winforms-methods-now-throw-argumentexception) | 5.0 |
+| [WinForms methods now throw ArgumentNullException](#winforms-methods-now-throw-argumentnullexception) | 5.0 |
 | [Removed controls](#removed-controls) | 3.1 |
 | [CellFormatting event not raised if tooltip is shown](#cellformatting-event-not-raised-if-tooltip-is-shown) | 3.1 |
 | [Control.DefaultFont changed to Segoe UI 9 pt](#default-control-font-changed-to-segoe-ui-9-pt) | 3.0 |
@@ -35,6 +36,10 @@ The following breaking changes are documented on this page:
 
 ***
 
+[!INCLUDE [invalid-args-cause-argumentexception](../../../includes/core-changes/windowsforms/5.0/invalid-args-cause-argumentexception.md)]
+
+***
+
 [!INCLUDE [null-args-cause-argumentnullexception](../../../includes/core-changes/windowsforms/5.0/null-args-cause-argumentnullexception.md)]
 
 ***

includes/core-changes/windowsforms/5.0/invalid-args-cause-argumentexception.md

@@ -0,0 +1,40 @@
+### WinForms methods now throw ArgumentException
+
+Some Windows Forms methods now throw an <xref:System.ArgumentException> for invalid arguments, where previously they did not.
+
+#### Change description
+
+Previously, passing arguments of an unexpected or incorrect type to certain Windows Forms methods would result in an indeterminate state. Starting in .NET 5.0, these methods now throw an <xref:System.ArgumentException> when passed invalid arguments.
+
+Throwing an <xref:System.ArgumentException> conforms to the behavior of the .NET runtime. It also improves the debugging experience by clearly communicating which argument is invalid.
+
+The following table lists the affected methods and parameters:
+
+| Method | Parameter name | Condition | Version added |
+|-|-|-|
+| <xref:System.Windows.Forms.TabControl.GetToolTipText(System.Object)?displayProperty=fullName> | `item` | Argument is not of type <xref:System.Windows.Forms.TabPage>. | 5.0 Preview 1 |
+
+#### Version introduced
+
+.NET 5.0 Preview 1
+
+#### Recommended action
+
+- Update the code to prevent passing invalid arguments.
+- If necessary, handle an <xref:System.ArgumentException> when calling the method.
+
+#### Category
+
+Windows Forms
+
+#### Affected APIs
+
+- <xref:System.Windows.Forms.TabControl.GetToolTipText(System.Object)?displayProperty=fullName>
+
+<!-- 
+
+### Affected APIs
+
+- `M:System.Windows.Forms.TabControl.GetToolTipText(System.Object)`
+
+-->

includes/core-changes/windowsforms/5.0/null-args-cause-argumentnullexception.md

@@ -1,4 +1,4 @@
-### WinForms APIs now throw ArgumentNullException
+### WinForms methods now throw ArgumentNullException
 
 Some Windows Forms methods now throw an <xref:System.ArgumentNullException> for null arguments, where previously they threw a <xref:System.NullReferenceException>.