running on a core I7, 16 GB ram 64 bit laptop. I have matlab m-files making figure plots with a couple dozen line handles encompassing 100's of thousands of points. 2016b performs faster in plotting them, while 2019a seems to hesitate between each set of lines. m-file code is no different between the two versions. the plots make use of the 'UserData' and 'Tag' functionality to store data in the lines, for use in extracting the data via selection/callbacks. Any obvious reason why 2019a is slower than 2016b in plotting?