diff --git a/src/uicmd.cc b/src/uicmd.cc
index 5d36077..7d86b07 100644
--- a/src/uicmd.cc
+++ b/src/uicmd.cc
@@ -87,7 +87,7 @@ static struct Tabgroup *tabgroups = NULL;
  */
 static BrowserWindow *UIcmd_tab_new(CustTabs *tabs, UI *old_ui, int focus);
 static void close_tab_btn_cb (Fl_Widget *w, void *cb_data);
-static char *UIcmd_make_search_str(const char *str);
+static std::string UIcmd_make_search_str(const char *str);
 static void UIcmd_set_window_labels(Fl_Window *win, const char *str);
 
 //----------------------------------------------------------------------------
@@ -731,10 +731,10 @@ void a_UIcmd::a_UIcmd_close_all_bw(void *)
  * Return a search string of the suffix if str starts with a
  * prefix of a search engine name and a blank
  */
-static char *UIcmd_find_search_str(const char *str)
+static std::optional< std::string > UIcmd_find_search_str(const char *str)
 {
    int p;
-   char *url = NULL;
+   std::optional< std::string > url;
    int len = strcspn(str, " ");
 
    if (len > 0 && str[len] != '\0') {
@@ -762,12 +762,12 @@ static char *UIcmd_find_search_str(const char *str)
 void a_UIcmd::a_UIcmd_open_urlstr(BrowserWindow *bw, const char *urlstr)
 {
    char *new_urlstr;
-   char *search_urlstr = NULL;
+   std::optional< std::string > search_urlstr;
    std::unique_ptr< DilloUrl > url;
    int ch;
 
    if ((search_urlstr = UIcmd_find_search_str(urlstr))) {
-      urlstr = search_urlstr;
+      urlstr = search_urlstr.value().c_str();
    }
    if (urlstr && *urlstr) {
       /* Filter URL string */
@@ -792,7 +792,6 @@ void a_UIcmd::a_UIcmd_open_urlstr(BrowserWindow *bw, const char *urlstr)
          a_UIcmd_open_url(bw, url.release());
       }
    }
-   dFree(search_urlstr);
 }
 
 /*
@@ -1164,12 +1163,13 @@ void a_UIcmd::a_UIcmd_open_file(void *vbw)
  * a string of keywords (separated by blanks) and the current search_url.
  * The search string is urlencoded.
  */
-static char *UIcmd_make_search_str(const char *str)
+static std::string
+UIcmd_make_search_str(const char *str)
 {
-   char *search_url, *l, *u, *c;
+   char *l, *u, *c;
    char *keys = a_Url_encode_hex_str(str),
         *src = (char*)dList_nth_data(prefs.search_urls, prefs.search_url_idx);
-   Dstr *ds = dStr_sized_new(128);
+   std::string search_url;
 
    /* parse search_url into label and url */
    if (a_Misc_parse_search_url(src, &l, &u) == 0) {
@@ -1177,22 +1177,20 @@ static char *UIcmd_make_search_str(const char *str)
          if (*c == '%')
             switch(*++c) {
             case 's':
-               dStr_append(ds, keys); break;
+               search_url+= keys; break;
             case '%':
-               dStr_append_c(ds, '%'); break;
+               search_url+= '%'; break;
             case 0:
                MSG_WARN("search_url ends with '%%'\n"); c--; break;
             default:
                MSG_WARN("illegal specifier '%%%c' in search_url\n", *c);
             }
          else
-            dStr_append_c(ds, *c);
+            search_url+= *c;
       }
    }
    dFree(keys);
 
-   search_url = ds->str;
-   dStr_free(ds, 0);
    return search_url;
 }
 
@@ -1204,9 +1202,8 @@ void a_UIcmd::a_UIcmd_search_dialog(BrowserWindow *bw)
    const char *query;
 
    if ((query = a_Dialog_input("Flenser: Search", "Search the Web:"))) {
-      char *url_str = UIcmd_make_search_str(query);
-      a_UIcmd_open_urlstr(bw, url_str);
-      dFree(url_str);
+      auto url_str = UIcmd_make_search_str(query);
+      a_UIcmd_open_urlstr(bw, url_str.c_str());
    }
 }