Change the provided properties to see how they affect the gridlines in gantt chart area.
Affect Item
ganttRows
topTierColumn
middleTierColumn
bottomTierColumn
currentDate
projectStart
projectFinish
Line Type
empty
thin
dashed
dotted
dashDot
Line Color
* valid value: color string
* toggle panel for the "Affect Item" option when you selected "ganttRows" item.
Set Interval Gridline Styles:
Interval Line Type
empty
thin
dashed
dotted
dashDot
Interval Line Color
* valid value: color string
Interval
* valid value: integer