some comments

Core/Src/app_gui.c

@@ -353,8 +353,9 @@ static void screen_menu(GuiEvent event, const char **options, menu_callback_t cb
             break;
 
         case GUI_EVENT_SCREEN_TICK:
+            // long text sliding animation
             if (tickNow - menu->change_time >= pdMS_TO_TICKS(500)) {
-                uint32_t textlen = strlen(options[menu->pos]) * 6;
+                const uint32_t textlen = strlen(options[menu->pos]) * 6;
                 if (textlen >= FBW - 2) {
                     if (textlen - menu->text_slide > FBW - 2) {
                         menu->text_slide += 1;
@@ -373,12 +374,13 @@ static void screen_menu(GuiEvent event, const char **options, menu_callback_t cb
 
         case GUI_EVENT_PAINT:
             for (int i = 0; i < menu->len; i++) {
-                bool current = menu->pos == i;
-                fbcolor_t color = !current;
-                fbpos_t y = 27 + i * 10;
+                // is the row currently rendered the selected row?
+                const bool is_selected = menu->pos == i;
+                const fbcolor_t color = !is_selected; // text color - black if selected, because it's inverted
+                const fbpos_t y = 27 + i * 10;
                 fb_rect(0, y, FBW, 10, !color);
-                fb_text(1 - (current ? menu->text_slide : 0), y + 1, options[i], FONT_5X7, color);
-                // ensure the text doesnt escape the screen
+                fb_text(1 - (is_selected ? menu->text_slide : 0), y + 1, options[i], FONT_5X7, color);
+                // ensure the text doesn't touch the edge (looks ugly)
                 fb_vline(FBW - 1, y, 10, !color);
                 fb_vline(0, y, 10, !color);
             }