Resolves iamstormtaylor/slate#3778: Check if editable target before handling paste event (#3779)

packages/slate-react/src/components/editable.tsx

@@ -946,11 +946,11 @@ export const Editable = (props: EditableProps) => {
             // when "paste without formatting" option is used.
             // This unfortunately needs to be handled with paste events instead.
             if (
+              hasEditableTarget(editor, event.target) &&
               !isEventHandled(event, attributes.onPaste) &&
               (!HAS_BEFORE_INPUT_SUPPORT ||
                 isPlainTextOnlyPaste(event.nativeEvent)) &&
-              !readOnly &&
-              hasEditableTarget(editor, event.target)
+              !readOnly
             ) {
               event.preventDefault()
               ReactEditor.insertData(editor, event.clipboardData)