Adding Instructions for enabling virtual_packet_logging

docs/using/visualization/generating_widgets.ipynb

@@ -575,11 +575,16 @@
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": null,
+   "cell_type": "markdown",
    "metadata": {},
-   "outputs": [],
-   "source": []
+   "source": [
+    "## Enabling `virtual_packet_logging` Property for Plotting \n",
+    "<div class=\"alert alert-info\">\n",
+    "\n",
+    "**Important:** The virtual packet logging capability must be active in order to produce SDEC Plot. Thus, make sure to set `virtual_packet_logging: True` in your configuration file. It should be added under `virtual` property of `spectrum` property, as described in [configuration schema](https://tardis-sn.github.io/tardis/using/components/configuration/configuration.html#spectrum).\n",
+    "\n",
+    "</div>"
+   ]
   }
  ],
  "metadata": {
@@ -598,7 +603,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.9"
+   "version": "3.8.8"
   },
   "notify_time": "5",
   "toc": {