[1.4.0b2] Track Mixer visuals stutter & lag

[fieldmanual2]

Steps to reproduce

play track, go to pattern, go to track mixer, hold shift - see mixer visuals stutter and lag

Attachments and links

IMG_2289.MOV

[fieldmanual2]

this is still occurs on 1.4.1b1, less lag but noticeable, see vid @ziej8asek

IMG_4671.MOV

[Jacknametrouble]

Fixed in firmware v1.5.0