fix: unregister npc overlay on shutdown (#2)

Author: iProdigy

src/main/java/com/pickpockethelper/HighlightManager.java

@@ -8,6 +8,8 @@
 import javax.inject.Inject;
 import javax.inject.Singleton;
 import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
 
 /**
  * Simplifies interaction with Runelite's overlay service.
@@ -20,17 +22,25 @@ public class HighlightManager {
 
     private final NpcOverlayService npcOverlayService;
 
-    private final HashMap<NPC, HighlightedNpc> targets = new HashMap<>();
+    private final Map<NPC, HighlightedNpc> targets = new HashMap<>();
+    private final Function<NPC, HighlightedNpc> isTarget = targets::get;
 
     @Inject
     public HighlightManager(PickpocketHelperConfig config, NpcOverlayService npcOverlayService, ClientThread clientThread) {
         this.config = config;
         this.npcOverlayService = npcOverlayService;
-        npcOverlayService.registerHighlighter(targets::get);
 
         clientThread.invoke(this::refresh);
     }
 
+    public void register() {
+        npcOverlayService.registerHighlighter(isTarget);
+    }
+
+    public void unregister() {
+        npcOverlayService.unregisterHighlighter(isTarget);
+    }
+
     /**
      * Format an NPC as a highlightedNPC, so it can be highlighted.
      * @param npc the NPC to be highlighted.

src/main/java/com/pickpockethelper/PickpocketHelperPlugin.java

@@ -147,13 +147,15 @@ protected void startUp() {
         overlayManager.add(statisticOverlay);
         overlayManager.add(timerOverlay);
         audioManager.init();
+        highlightManager.register();
         hooks.registerRenderableDrawListener(this::shouldRenderEntity);
     }
 
     @Override
     protected void shutDown() {
         hooks.unregisterRenderableDrawListener(this::shouldRenderEntity);
         highlightManager.clearTargets();
+        highlightManager.unregister();
         overlayManager.remove(statusOverlay);
         overlayManager.remove(splasherOverlay);
         overlayManager.remove(statisticOverlay);