Most themes has been removed in self-hosted environment

[Wertisdk]

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Describe the bug
After upgrading from 22.1.8 to 24.3.1 mos of the themes are no longer available in the themes menu, and do not apply when using the ui urlParam - like so: ui=simple.
However, when using the same urlParams on app.draw.io, this works fine.

https://[self-hosted-url]/?ui=simple&stealth=1&splash=0
The default theme is applied and only the themes 'Automatic', 'Classic' and 'Minimal' are available.
This worked in v22.1.8

https://app.diagrams.net/?ui=simple&stealth=1&splash=0
The simple theme is applied and multiple themes are available

To Reproduce
Steps to reproduce the behavior:

1. Open a self-hosted version of drawio with the repo checked out to tags/v24.1.3 and with the ui urlParam set to 'simple' (?ui=simple)
2. Observe that the simple theme is not applied
3. Open Extras > Themes
4. Observe that only 'Automatic', 'Classic' and 'Minimal' are available

Expected behavior
You should be able to set the theme to any of the supported themes and themes should be available when self-hosting as well.

If this is intended behaviour, it would be nice if this was stated clearly in:

1. The github repo description
2. In the blogpost about configuring the editor (https://www.drawio.com/doc/faq/configure-diagram-editor)
3. In the changelog

Screenshots
Screenshot of available themes in self-hosted environment

draw.io version (In the Help->About menu of the draw.io editor):

• draw.io version 24.1.3

Desktop (please complete the following information):

• OS: Windows 11
• Browser: Chrome
• Browser Version: 124.0.6367.119

Smartphone (please complete the following information):
N/A

I tested the problem in incognito/private mode with all browser extensions switched off, write "yes" below:

• yes