October 11, 2022-KB5017266 Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 10, version 20H2, Windows 10 Version 21H1, and Windows 10 Version 21H2

WPF₁

- Addresses an issue of WPF apps not working with "Text Cursor Indicator" enabled when using RichTextBox.

- Addresses an issue to allow users to adjust column width for Datagrid and Gridview controls using keybord

- Addresses issues arising in TreeView (or ListBox/DataGrid with grouping enabled) when changing the underlying collection(s) while also collapsing or expanding TreeView nodes. Scrolling actions, especially "short" actions like LineUp or MouseWheelUp, can result in poor outcomes: hangs, crashes, unexpected scrolling, gaps in the display, etc.

- Addresses an issue where opening a tooltip causes an ArgumentOutOfRangeException, when the app has changed the floating point control word.

- Addresses an issue where invoking a synchronization Wait on the UI thread can lead to a render-thread failure, due to unexpected re-entrancy.

- Addresses an issue where DWM failures can cause WPF's render thread to fail. An app can opt-in to the behavior of ignoring all DwmFlush errors by setting a regkey in
HKCU\Software\Microsoft\Avalon.Graphics\IgnoreDwmFlushErrors
or
HKLM\Software\Microsoft\Avalon.Graphics\IgnoreDwmFlushErrors
whose name is the full path to the .exe that wants to opt-in, and whose DWORD value is 1.

Winforms

- Improved keyboard navigation in ToolStrip ComboBox and TextBox items.

- Improved color contrast in System.Windows.Forms.DataGridView control's link cells.

- Enabled Narrator to focus on System.Windows.Forms.DataGridView control even if it's empty.

Workflow

- Addresses an issue when users interact with the Workflow Designer, they might encounter incorrectly disabled context menu items when right clicking on a variable in the component variables list.

.NET Runtime

- Improved reliability of managed debugging on arm64.

- Adjusted GC Heap Hard Limit configuration, as well as processor interpretation for .NET Framework container scenarios.

- Improved security of code identified by internal compliance scans.

- Improved deterministic output capability in ilasm.exe.

Networking

- Addresses an issue when Ssl negotiation can hang indefinitely when client certificates are used when TLS 1.3 is negotiated. Before the change renegotiation (PostHandshakeAuthentiction) would fail and SslStream or HttpWebRequest would observe timeout. Possible workaround is disabling TLS 1.3 either via Switch.System.Net.DontEnableTls13 AppContext or via OS registry.

Release Channel

Available

Next Step

Windows Update and Microsoft Update

Yes

None. This update will be downloaded and installed automatically from Windows Update.

Windows Update for Business

No

None. These changes will be included in the next security update to this channel. For more information about Windows Update for Business go to the Windows Update for Business website.

Microsoft Update Catalog

Yes

To get the standalone package for this update, go to the Microsoft Update Catalog website.

Windows Server Update Services (WSUS)

Yes

This update will automatically sync with WSUS if you configure Products and Classifications as follows:

Product: Windows 10, version 20H2, Windows 10 Version 21H1, and Windows 10 Version 21H2

Classification: Updates