Possible slowness turning on and off tracks in synteny view

[cmdcolin]

This was just somewhat unexpected but toggling a track can be slow, maybe with the linear synteny view particularly

Example: Visit https://jbrowse.org/code/jb2/v1.6.5/?config=test_data%2Fconfig_synteny_grape_peach.json&session=share-kY4TSOUAUD&password=wHcxI

Then turn off or on the synteny track

Large second+ long delay

Profiling is a little weird, has a big 1.5second delay recalculating styles and then there is i believe rerendering of the LGV tracks also that happens

[cmdcolin]

is probably mostly related to the svg features tracks, if they are off it is instantaneous

[cmdcolin]

note that a weird amount of slowness can happen when clicking a feature on a gene track >1second

our demo link on the homepage https://jbrowse.org/code/jb2/v1.6.9/?session=share-HShsEcnq3i&password=nYzTU

clicking a gene results in about 0.8s of blocking there, which is due to re-rendering the gene track after clicking a feature, not related to the drawer opening. not exactly sure why the gene track has to re-render though

[cmdcolin]

basically boils down to need for canvasfeatures for gene tracks