【APPCenter】Crash编号：15（属性面板）

PDF Office/PDF Master/Class/PDFWindowController/Side/RightSide/AnnotationProperty/KMGeneralAnnotationViewController.swift

@@ -1080,7 +1080,7 @@ let KMColorPickerViewHeight: CGFloat = 64
         if let data = newValue?.isEqual(to: oldValue), data {
             return
         }
-        if keyPath == "string" {
+        if keyPath == "string" || keyPath == "contents"{
             if newValue == nil || newValue is NSNull {
                 return
             }