Gantt chart option to hide lines for days

[hski-github]

I am using Gantt v1.0 and looking at a timescale of 2-5 years. The vertical lines for days are always show, even if I choose only "Month" and "Year" in the level of detail in the time axis hierarchy.

Everything gets grey because of the 1000 lines and also the drawing gets slow I think.

If in the time axis hierarchy I have selected "Month", then I would expect that also the daily lines are hidden, not only the labels. And even monthly lines are hidden if I select "Year" in the time hierarchy.