diff --git a/core/lib/canary_web/live/dev/understander_live.ex b/core/lib/canary_web/live/dev/understander_live.ex
index 29eedaa5..8d843593 100644
--- a/core/lib/canary_web/live/dev/understander_live.ex
+++ b/core/lib/canary_web/live/dev/understander_live.ex
@@ -7,7 +7,13 @@ defmodule CanaryWeb.Dev.UnderstanderLive do
     ~H"""
     <div>
       <form phx-change="source">
-        <Primer.select name="Source" options={@source_names} is_form_control />
+        <Primer.select
+          name="source[]"
+          options={Enum.map(@sources, & &1.name)}
+          is_form_control
+          is_multiple
+          is_auto_height
+        />
       </form>
 
       <form class="flex flex-row gap-2 mt-4 items-center" phx-submit="submit">
@@ -30,36 +36,34 @@ defmodule CanaryWeb.Dev.UnderstanderLive do
   @impl true
   def mount(_params, _session, socket) do
     sources = Canary.Sources.Source |> Ash.read!()
-    source_names = sources |> Enum.map(& &1.name)
-    current_source = sources |> Enum.at(0)
 
     socket =
       socket
       |> assign(query: "")
       |> assign(result: [])
       |> assign(sources: sources)
-      |> assign(source_names: source_names)
-      |> assign(current_source: current_source)
+      |> assign(selected: [])
 
     {:ok, socket}
   end
 
   @impl true
-  def handle_event("source", %{"Source" => source_name}, socket) do
-    current_source =
+  def handle_event("source", %{"source" => sources}, socket) do
+    selected =
       socket.assigns.sources
-      |> Enum.find(&(&1.name == source_name))
+      |> Enum.filter(&(&1.name in sources))
 
     socket =
       socket
-      |> assign(current_source: current_source)
+      |> assign(selected: selected)
 
     {:noreply, socket}
   end
 
   @impl true
   def handle_event("submit", %{"query" => query}, socket) do
-    {:ok, words} = Canary.Query.Understander.run([socket.assigns.current_source], query)
+    keywords = Canary.Query.Understander.keywords(socket.assigns.selected)
+    {:ok, words} = Canary.Query.Understander.run(query, keywords)
     {:noreply, socket |> assign(query: query, result: words)}
   end
 end