Glitchy graphics in parts editor


I have got a small issue in parts editor.
Steps to reproduce an issue:
1.Drop audio file in project
2.“Audio->events to part” on it
3.Enter audio parts editor
4.Make a few cuts, select all
5.Try to drag this selection

Some parts becomes hidden (while dragging) depending on what part you are dragging.
Sometimes it happens even after dropping an audio.

kind regards, Alexander