fix: erase undo/redo history on doc change/refresh

frappe/public/js/frappe/form/form.js

@@ -379,6 +379,8 @@ frappe.ui.form.Form = class FrappeForm {
 
 		cur_frm = this;
 
+		this.undo_manager.erase_history();
+
 		if(this.docname) { // document to show
 			this.save_disabled = false;
 			// set the doc

frappe/public/js/frappe/form/undo_manager.js

@@ -33,4 +33,9 @@ export class UndoManager {
 		// keyboard interactions shouldn't have long running
 		frappe.show_alert(msg, 3);
 	}
+
+	erase_history() {
+		this.undo_stack = [];
+		this.redo_stack = [];
+	}
 }