--- alexandria-book-collection-manager-0.7.6/lib/alexandria/ui/new_book_dialog.rb.nothread	2020-11-03 00:29:34.194485720 +0900

+++ alexandria-book-collection-manager-0.7.6/lib/alexandria/ui/new_book_dialog.rb	2020-11-03 00:34:01.426386821 +0900

@@ -281,15 +281,17 @@ module Alexandria

                          get_images_async

                          false # continue == false if you get to here. Stop timeout.

                        end

-                     else

+                     elsif @find_thread

                        # Stop if the book find thread has stopped.

                        @find_thread.alive?

+                     else

+                       true

                      end

           # continue == false if @find_error OR if results are returned

           # timeout ends if continue is false!

           # @find_thread.alive? happens after find_thread is done

-          unless continue || @find_thread.alive? || @destroyed

+          unless continue || (@find_thread && @find_thread.alive?) || @destroyed

             notify_end_add_by_isbn

             @button_add.sensitive = false

           end