free(self);
 }
 
+static void ui_helpline__pop(void)
+{
+       newtPopHelpLine();
+}
+
+static void ui_helpline__push(const char *msg)
+{
+       newtPushHelpLine(msg);
+}
+
+static void ui_helpline__vpush(const char *fmt, va_list ap)
+{
+       char *s;
+
+       if (vasprintf(&s, fmt, ap) < 0)
+               vfprintf(stderr, fmt, ap);
+       else {
+               ui_helpline__push(s);
+               free(s);
+       }
+}
+
+static void ui_helpline__fpush(const char *fmt, ...)
+{
+       va_list ap;
+
+       va_start(ap, fmt);
+       ui_helpline__vpush(fmt, ap);
+       va_end(ap);
+}
+
+static void ui_helpline__puts(const char *msg)
+{
+       ui_helpline__pop();
+       ui_helpline__push(msg);
+}
+
 static char browser__last_msg[1024];
 
 int browser__show_help(const char *format, va_list ap)
        backlog += ret;
 
        if (browser__last_msg[backlog - 1] == '\n') {
-               newtPopHelpLine();
-               newtPushHelpLine(browser__last_msg);
+               ui_helpline__puts(browser__last_msg);
                newtRefresh();
                backlog = 0;
        }
        if (fp == NULL)
                goto out_free_str;
 
-       newtPushHelpLine("Press ESC to exit");
+       ui_helpline__push("Press ESC to exit");
        newtGetScreenSize(&cols, &rows);
        tree = newtListbox(0, 0, rows - 5, NEWT_FLAG_SCROLL);
 
        newtFormRun(form, &es);
        newtFormDestroy(form);
        newtPopWindow();
-       newtPopHelpLine();
+       ui_helpline__pop();
 out_free_str:
        free(str);
 }
        if (browser == NULL)
                return -1;
 
-       newtPushHelpLine(helpline);
+       ui_helpline__push(helpline);
 
        hist_browser__title(msg, sizeof(msg), input_name,
                            dso_filter, thread_filter);
 do_annotate:
                if (choice == annotate) {
                        if (browser->selection->map->dso->origin == DSO__ORIG_KERNEL) {
-                               newtPopHelpLine();
-                               newtPushHelpLine("No vmlinux file found, can't "
+                               ui_helpline__puts("No vmlinux file found, can't "
                                                 "annotate with just a "
                                                 "kallsyms file");
                                continue;
                        map_symbol__annotate_browser(browser->selection, input_name);
                } else if (choice == zoom_dso) {
                        if (dso_filter) {
-                               newtPopHelpLine();
+                               ui_helpline__pop();
                                dso_filter = NULL;
                        } else {
-                               snprintf(msg, sizeof(msg),
-                                        "To zoom out press -> + \"Zoom out of %s DSO\"",
-                                        dso->kernel ? "the Kernel" : dso->short_name);
-                               newtPushHelpLine(msg);
+                               ui_helpline__fpush("To zoom out press -> + \"Zoom out of %s DSO\"",
+                                                  dso->kernel ? "the Kernel" : dso->short_name);
                                dso_filter = dso;
                        }
                        hists__filter_by_dso(self, dso_filter);
                                goto out;
                } else if (choice == zoom_thread) {
                        if (thread_filter) {
-                               newtPopHelpLine();
+                               ui_helpline__pop();
                                thread_filter = NULL;
                        } else {
-                               snprintf(msg, sizeof(msg),
-                                        "To zoom out press -> + \"Zoom out of %s(%d) thread\"",
-                                        (thread->comm_set ? thread->comm : ""),
-                                        thread->pid);
-                               newtPushHelpLine(msg);
+                               ui_helpline__fpush("To zoom out press -> + \"Zoom out of %s(%d) thread\"",
+                                                  thread->comm_set ? thread->comm : "",
+                                                  thread->pid);
                                thread_filter = thread;
                        }
                        hists__filter_by_thread(self, thread_filter);
        use_browser = true;
        newtInit();
        newtCls();
-       newtPushHelpLine(" ");
+       ui_helpline__puts(" ");
 }
 
 void exit_browser(bool wait_for_ok)