WPF touch application (partially) freezes on .NET Framework 4.7

Why it break in .NET Framework 4.7 for Windows10 Creators Update?

My friend lsj download the source code from https://referencesource.microsoft.com and find the .NET 4.7 for Windows 10 Creators Update have not add lock to WispLogic.CoalesceAndQueueStylusEvent and the other add the lock.

So it only break in .NET Framework 4.7 for Windows10 Creators Update. And .NET Framework 4.7 RTM add the lock to WispLogic.CoalesceAndQueueStylusEvent and fix it.

Which version add lock?

• .NET 4.7 RTM
• .NET 4.7.2 RS4
• .NET 4.7.2 ZDP
• .NET 4.8 RTM

Which version remove lock?

• .NET 4.6.2 RS1
• .NET 4.6.2 RTM
• .NET 4.7 RS2
• .NET 4.7.1 RS3
• .NET 4.7.1 Downlevel

The funny thing is .NET 4.7 RTM add the lock to WispLogic.CoalesceAndQueueStylusEvent and the .NET 4.7.1 Downlevel remove it.

The .NET 4.7.2 for Windows 10 April 2018 Creators Update is the frist version to add lock and it seems fix in .NET 4.7.2 not fix in .NET 4.7.1