Hi GHGMX,
Thank you for reaching Microsoft Community. We're sorry for the trouble this has caused you.
I'm aware of the problem you're having with your Surface Pro 9 and Slim Pen 2, in which diagonal lines jitter as you draw them. I am here to help and let us work on this together. Allow me to ask some questions.
- May I know which Surface Pro 9 configuration you have? The Intel or 5G(SQ3)?
- When did this started happening?
- What build version of Windows you are currently running?
To troubleshoot the jittering issue with diagonal lines, please try the following steps:
Make sure that your Surface Pro 9 and Slim Pen 2 are fully updated with the latest software and firmware updates. You can check for updates by going to Settings > Windows Update > Check for updates.
Run Surface Diagnostic Toolkit
See: Fix common Surface problems using the Surface Diagnostic Toolkit (microsoft.com)
Try adjusting the pen pressure sensitivity settings.
- Open the Surface app: You can find this app pre-installed on your Surface device, or you can download it from the Microsoft Store.
- Select the Pen category: On the left side of the app, you’ll see various categories. Tap on ‘Pen’.
- Adjust Pen Pressure Sensitivity: Here, you’ll find a slider under ‘Pen Pressure Sensitivity’. Slide it to adjust the sensitivity to your liking. The further right you go, the more pressure you’ll need to apply for a response.
Check if the issue persists when using a different drawing app. If the issue only occurs in a specific app, try reinstalling the app.
For other troubleshooting guide, see Troubleshoot your Surface Pen - Microsoft Support.
Let me know how it goes.
Kind regards,
Lavenia