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Since KB5001337 was applied to Windows 10 version 1909, the vertical scrollbar in our VB6 application now shows as a white box instead and no events are actioned from the vertical scrollbar meaning that scrolling is now disabled on all screens that use this control.
Later versions of windows 10 have not had this update and they are all working ok.
If the update is removed then the functionality starts working again.
Is there anything our customers on this version of Windows can do apart from updating to a later version of windows.
They are all on the enterprise version of windows so will still be in service for this version of windows for the foreseeable future and they did not have any plans to immediately update their version of windows and they have a vast estate to maintain so it will give them a problem to either keep the update rolled back or to upgrade to a new version of windows.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(156.8, 43%, 25%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EJL%3C/text%3E%3C/svg%3E)
There are now many reported issues in different Software for 1337, eg
https://www.reddit.com/r/Windows10/comments/mqvhpa/kb5001330_bad_gaming_performance/
Hi Johan,
Yes, we saw those but thanks for posting. There is another control a DB Grid also suffering from the same issue. We were hoping that as the problem became more widespread that Microsoft might do something about them or someone might find a workaround (other than removing the update or moving to a later version of windows) but we haven't heard anything yet.
Ok. Do you have a simple reproduce example that does not include your whole code?
Yes, if in VB6, if you just create an application with a single form that has the Vertical Scrollbar control on it, with no other code and then compile that as an executable. That form displays the vertical scrollbar ok on later versions of windows than version 1909 and on version 1909 without the windows update applied but on 1909 with the windows update applied the vertical scrollbar is not shown and instead a white space is visible.
We produced such a test executable to confirm that the problem was just with this control and it wasn't anything else in our application.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(99.2, 39%, 19%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ER%3C/text%3E%3C/svg%3E)
It works fine on my computer, I don't have W10 1909 but 20H2 (with latest update)
Try to upgrade it, maybe it will work. FYI, 1909 end of support is in one month.
Hi Romain,
Thanks for the reply.
The customer with the issue is on the Enterprise version of Windows, so I believe they will still be in support after May 2021.
On specific machines they have rolled back the update and now the vertical scrollbar works ok again and we are on later versions of windows and have never experienced the problem.
The customer has thousands of machines running many different applications and it will be a major undertaking for them to do an unplanned upgrade to a new version of windows but unless there is a workaround then obviously they will have no alternative.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(86.4, 1%, 18%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EIA%3C/text%3E%3C/svg%3E)
The bug also affects WPF applications hosting windows forms controls using WindowsFormsHost.
Debugging the issue hints that the update introduces a bug in the ScrollBar Win32 window class (bad value for cbWndExtra), possibly in user32.dll.
Hi Ingeborg,
Thank you, that's interesting. We have a WPF application too but I believe the customers with that application are on later versions of windows, luckily.
I don't suppose reverting User32.dll to a prior version might solve it or would introduce lots of other errors?
I wouldn't try just reverting user32.dll, you have no idea of what might happen. Uninstalling KB5001337 resolves the issue for WPF apps as well,
Fair enough.