Fix issue 14094: After reducing the form width, clicking the ToolStrip options triggers a Win32Exception error

src/System.Windows.Forms/System/Windows/Forms/Controls/ToolStrips/ToolStripControlHost.cs

@@ -801,7 +801,21 @@ protected virtual void OnUnsubscribeControlEvents(Control? control)
     /// </remarks>
     private void SyncControlParent()
     {
-        ReadOnlyControlCollection? newControls = GetControlCollection(ParentInternal);
+        ToolStrip? parent = ParentInternal;
+
+        if (parent is null || _control is null)
+        {
+            return;
+        }
+
+        if (_control.IsHandleCreated && !parent.IsHandleCreated)
+        {
+            // The hosted control already has a native handle (for example, when moving to the
+            // overflow dropdown). Ensure the ToolStrip parent has a handle before reparenting.
+            parent.CreateControl(ignoreVisible: true);
+        }
+
+        ReadOnlyControlCollection? newControls = GetControlCollection(parent);
         newControls?.AddInternal(_control);
     }
 

src/test/unit/System.Windows.Forms/System/Windows/Forms/ToolStripControlHostTests.cs

@@ -222,6 +222,40 @@ public void ToolStripControlHost_AccessibleName_SetDisposed_ThrowsObjectDisposed
         Assert.Throws<ObjectDisposedException>(() => item.AccessibleName = "value");
     }
 
+    [WinFormsFact]
+    public void ToolStripControlHost_ReparentToOverflowWithCreatedControl()
+    {
+        using Form form = new();
+        using ToolStrip toolStrip = new()
+        {
+            Dock = DockStyle.None,
+            CanOverflow = true
+        };
+        using ToolStripComboBox comboBox = new();
+        using ToolStripProgressBar progressBar = new();
+
+        toolStrip.Items.AddRange([comboBox, progressBar]);
+        form.Controls.Add(toolStrip);
+
+        form.Show();
+
+        Assert.True(toolStrip.IsHandleCreated);
+        _ = comboBox.Control.Handle;
+        _ = progressBar.Control.Handle;
+        Assert.True(comboBox.Control.IsHandleCreated);
+        Assert.True(progressBar.Control.IsHandleCreated);
+
+        toolStrip.AutoSize = false;
+        toolStrip.Width = 10;
+        toolStrip.PerformLayout();
+
+        Assert.True(toolStrip.OverflowButton.Visible);
+
+        toolStrip.OverflowButton.DropDown.CreateControl(ignoreVisible: true);
+
+        Assert.True(toolStrip.OverflowButton.DropDown.IsHandleCreated);
+    }
+
     [WinFormsTheory]
     [EnumData<AccessibleRole>]
     public void ToolStripControlHost_AccessibleRole_Set_GetReturnsExpected(AccessibleRole value)