【注释】点击注释工具栏崩溃了一次 -- 修复

PDF Office/PDF Master/Class/Document/KMMainDocument.swift

@@ -592,7 +592,7 @@ typealias KMMainDocumentCloudUploadHanddler = (@escaping(Bool, String)->()) -> (
             
             let dic = notification.object as? NSDictionary
             if dic?["object"] is CPDFAnnotation {
-                let annotation : CPDFAnnotation = dic?["object"] as? CPDFAnnotation ?? CPDFAnnotation()
+                guard let annotation = dic?["object"] as? CPDFAnnotation else { return }
                 document = annotation.page.document
 
             } else if dic?["object"] is CPDFListView {