Update the movement tracking flags in the GM client, becauase the user isn't allowed to modify them

src/movement_tracking.js

@@ -1,4 +1,5 @@
 import {measureDistances} from "./compatibility.js";
+import {updateCombatantDragRulerFlags} from "./socket.js";
 import {getTokenShape} from "./util.js";
 
 function initTrackingFlag(combatant) {
@@ -54,7 +55,7 @@ export async function trackRays(token, rays) {
 			waypoints.push(ray.A);
 		}
 	}
-	await combat.updateEmbeddedEntity("Combatant", {_id: combatant._id, flags: combatant.flags}, {diff: false});
+	await updateCombatantDragRulerFlags(combat, combatant, dragRulerFlags);
 }
 
 export function getMovementHistory(token) {

src/socket.js

@@ -0,0 +1,17 @@
+let socket;
+
+Hooks.once("socketlib.ready", () => {
+	socket = socketlib.registerModule("drag-ruler");
+	socket.register("updateCombatantDragRulerFlags", _socketUpdateCombatantDragRulerFlags);
+});
+
+export async function updateCombatantDragRulerFlags(combat, combatant, flags) {
+	const combatId = combat.id;
+	const combatantId = combatant._id;
+	return socket.executeAsGM(_socketUpdateCombatantDragRulerFlags, combatId, combatantId, flags);
+}
+
+async function _socketUpdateCombatantDragRulerFlags(combatId, combatantId, flags) {
+	const combat = game.combats.get(combatId);
+	return combat.updateEmbeddedEntity("Combatant", {_id: combatantId, flags: {dragRuler: flags}}, {diff: false});
+}