Prevent cleaning graph state on undo/redo (#2255)

* Prevent cleaning graph state on undo/redo

* Remove pause rendering due to LG bug

web/extensions/core/undoRedo.js

@@ -71,24 +71,21 @@ function graphEqual(a, b, root = true) {
 }
 
 const undoRedo = async (e) => {
+	const updateState = async (source, target) => {
+		const prevState = source.pop();
+		if (prevState) {
+			target.push(activeState);
+			isOurLoad = true;
+			await app.loadGraphData(prevState, false);
+			activeState = prevState;
+		}
+	}
 	if (e.ctrlKey || e.metaKey) {
 		if (e.key === "y") {
-			const prevState = redo.pop();
-			if (prevState) {
-				undo.push(activeState);
-				isOurLoad = true;
-				await app.loadGraphData(prevState);
-				activeState = prevState;
-			}
+			updateState(redo, undo);
 			return true;
 		} else if (e.key === "z") {
-			const prevState = undo.pop();
-			if (prevState) {
-				redo.push(activeState);
-				isOurLoad = true;
-				await app.loadGraphData(prevState);
-				activeState = prevState;
-			}
+			updateState(undo, redo);
 			return true;
 		}
 	}

web/scripts/app.js

@@ -1559,9 +1559,12 @@ export class ComfyApp {
 	/**
 	 * Populates the graph with the specified workflow data
 	 * @param {*} graphData A serialized graph object
+	 * @param { boolean } clean If the graph state, e.g. images, should be cleared
 	 */
-	async loadGraphData(graphData) {
-		this.clean();
+	async loadGraphData(graphData, clean = true) {
+		if (clean !== false) {
+			this.clean();
+		}
 
 		let reset_invalid_values = false;
 		if (!graphData) {