diff --git a/js/game.js b/js/game.js
index ebd989d..6041e22 100644
--- a/js/game.js
+++ b/js/game.js
@@ -2455,6 +2455,28 @@ export class Level extends LevelInterface {
             }
             this._do_extra_cooldown(tile);
         }
+        
+        //update static_on_tic_tiles
+        //TODO: if which on_tic happens first ever matters, this will introduce a time travel bug where the order is changed by changing tiles then undoing that. hmm
+        if (old_type.on_tic && !new_type.on_tic)
+        {
+            //search array and remove
+            for (let i = 0; i < this.static_on_tic_tiles.length; ++i)
+            {
+                if (this.static_on_tic_tiles[i] == tile)
+                {
+                    this.static_on_tic_tiles.splice(i, 1);
+                    break;
+                }
+            }
+        }
+        else if (!old_type.on_tic && new_type.on_tic)
+        {
+            //add to end of array
+            this.static_on_tic_tiles.push(tile);
+        }
+        
+        //TODO: update circuit networks?
     }
 
     // Have an actor try to pick up a particular tile; it's prevented if there's a no sign, and the