This is a bug in the 2024-12 release of the Eclipse Scout SDK plugin.

You can try to update your Eclipse 2024-12 to the nightly version which includes a fix:

1. Go to Help -> Install new Software...
2. Enter "https://download.eclipse.org/scout/nightly/13.0/" in the "Work with" URL field and hit enter to populate the list.
3. In the list below category "Scout Application Development SDK" select "Eclipse Scout SDK" (choose at least version 13.0.0.20241209-2344)
4. Press Next and wait until all alternate solutions have been computed.
5. Choose alternate solution "Update my installation to be compatible with the items being installed" and press Next. This uninstalls the existing and installs the nightly version.
6. On the "Install Details" page review the config and press Finish.
7. Restart the IDE after the changes have completed.