[Cin] Timeline performance

Hi all. I have been trying some video editing with Cinelerra. It seems a very powerfull program but I am surprised of the clunkyness of timeline when I move video pieces, or select them for moving. My tests are very humble. Only two pieces of video of no more than 20 seconds. It is very frustrating to be precise enough when moving parts. Is it normal? Perhaps some bug with my media or configuration? Video composition in previewer is fast and very good, but not commented simple operations. Comparing other options, like Olive editor, in which working with parts is very fast and precise I ask myself if there is space for Cinelerra optimizations in this matter. Thank you very much for your work :) Greets. -- David