In Java Card, "classic" (old Java Card 2) projects can include generated "proxies" to work with multi-threaded Java Card 3 projects.  So, for a shareable object, Java Card will generate a "proxy" object which synchronizes access to the non-threaded Java Card 2 object.  We support editing of these generated sources in Java Card 3 (by default they are just generated at compile time).

Proxy sources are in a specific directory for Java Card projects.  That directory has a different classpath which includes the Java Card 3 APIs.

org.netbeans.javacard.project.JCProject's ClassPathProvider provides the correct classpath - it detects if a source is in the proxies source directory and provides a different classpath.

Such sources are, correctly, not marked with errors.

However, the source file itself always has an error badge, and the following is logged:

WARNING [org.netbeans.modules.java.source.tasklist.IncorrectErrorBadges]: Incorrect error badges detected, file=H:\tmp\ClassicApplet19\proxies\classicapplet19\proxy\Proxy1.java.
WARNING [org.netbeans.modules.java.source.tasklist.IncorrectErrorBadges]: Going to recompute root=H:\tmp\ClassicApplet19\proxies, files in error=[file:/H:/tmp/ClassicApplet19/proxies/classicapplet19/proxy/Proxy1.java].

To reproduce:
1. Build javacard.kit and javacard.ri.bundle
2. Create a new Java Card > Classic Applet project.
3. Add the following classes:
package classicapplet19;
import javacard.framework.Shareable;
public interface X extends Shareable {
    public byte getFoo();
}
package classicapplet19;
public class XI implements X {
    public byte getFoo() {
        return 42;
    }
}
4. Right click the project and choose Generate SIO Proxies (this will add a new source root).
5. Open the generated Proxy1.java.  No error markings in the editor, but the file's node always has an error badge.

Is there some way to work around this with an additional source group or something?