Yeray

Hello, The issue appears when all the gantt bars added have a label. If you add at least one gantt bar with an empty label this issue shouldn't appear. The problem is, when the all the points have a label, TChart assumes all of them are in different and regular Y positions and tries to calculate a step to skip some points and optimize the calculation of the labels to be drawn.

I use to recommend adding a dummy series with ShowInLegend set to False. In this case this should do it: Chart1.Draw; Chart1.Axes.Left.Automatic:=False; Chart1.Axes.Right.Automatic:=False; with Chart1.AddSeries(TLineSeries) do begin ShowInLegend:=False; VertAxis:=aBothVertAxis; end;