Windows context menu handler slows down context menu opening by a lot

[JosefNemec]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I have searched for it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

When Nextcloud desktop client is installed, it takes unreasonably long to open file/folder context menu in file explorer. This is caused by Nextcloud context menu handler, which I confirmed using ShellExView utility which allows you to disable individual shell extensions. Disabling Nextcloud context menu handler immediately fixed the issue. It also doesn't matter if this is file system item inside or outside of synced folder.

Here's a video demonstrating the issue:

shexview_vfqySv6Ar2.mp4

Steps to reproduce

• Right-click on a file or a folder in Windows file explorer while Nextcloud desktop client is installed
• Observe how long it takes for context menu to open

Expected behavior

The context menu open without any slow down.

Which files are affected by this bug

Any file or folder

Operating system

Windows

Which version of the operating system you are running.

Windows 10 22H2 (everything updated)

Installation method

Official Windows MSI

Nextcloud Server version

33.0.7

Nextcloud Desktop Client version

34.0.1

Did this occur after an update or on a clean installation?

Clean desktop client installation

Are you using the Nextcloud Server Encryption module?

No

Are you using an external user-backend?

• Default internal user-backend
• LDAP or Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

Additional info

I'm not attaching debug archive since it looks like it contains sensitive information. If you want, I can't send it to you via private channels.

[JosefNemec]

So immediately after I posted this, I tried to test if restarting Nextcloud client would fix it, and indeed it does fix it. So currently I can't reproduce it anymore. Let me know if you still want my debug package and how can I send it to you.