Always render all sources from default target

cmd/frontend/handler.go

@@ -13,6 +13,7 @@ import (
 
 	st "git.ipng.ch/ipng/nginx-logtail/internal/store"
 	pb "git.ipng.ch/ipng/nginx-logtail/proto/logtailpb"
+	"google.golang.org/grpc"
 )
 
 // Handler is the HTTP handler for the frontend.
@@ -526,7 +527,21 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		trendCh <- trendResult{resp, err}
 	}()
 	go func() {
-		resp, err := client.ListTargets(ctx, &pb.ListTargetsRequest{})
+		// Always query the default target for ListTargets so we get the full
+		// list of available sources even when viewing a specific collector.
+		ltClient := client
+		var ltConn *grpc.ClientConn
+		if params.Target != h.defaultTarget {
+			c, cl, err := dial(h.defaultTarget)
+			if err == nil {
+				ltConn = c
+				ltClient = cl
+			}
+		}
+		resp, err := ltClient.ListTargets(ctx, &pb.ListTargetsRequest{})
+		if ltConn != nil {
+			ltConn.Close()
+		}
 		if err != nil {
 			ltCh <- nil
 		} else {