Bug 175742 [Markers] contributed marker resolutions only showing first contribution
Debug is trying to add a marker resolution for a quick fix to repair deprecated JRE variables on the build path. When we contribute our resolution generator for org.eclipse.jdt.core.buildpath_problem marker types with a DEPRECATED_VARIABLE id attribute, we find that our resolution is always over-written by the junit generator. It seems that the MarkerHelpRegistry does not allow more than one generator per query result (in our case DEPRECATED_VARIABLE is the query result, same with junit's contribution). I would expect that you could have more than one quickfix for a given issue (in this case what to do about deprecated build path variables).
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/registry/MarkerHelpRegistry.java
"Unable to instantiate resolution generator", e.getStatus()); 
                    }
                    if (generator != null) {
                        IMarkerResolution[] generatedResolutions = generator
                                .getResolutions(marker);
                        for (int i = 0; i < generatedResolutions.length; i++) {
                            resolutions.add(generatedResolutions[i]);
                        }
                    }
                }
            }
        }
        return (IMarkerResolution[]) resolutions
                .toArray(new IMarkerResolution[resolutions.size()]);
    }
    /**
     * Adds a help query to the registry.
     * 
     * @param query a marker query
     * @param result a result for the given query
     * @param element the configuration element defining the result
     */
    public void addHelpQuery(MarkerQuery query, MarkerQueryResult result,
            IConfigurationElement element) {
        addQuery(helpQueries, query, result, element);
    }
    /**
     * Adds a resolution query to the registry.
     * 
     * @param query a marker query