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

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});
+}