Specifies the color of the diagonal and third lines that aid editing.
Use DisplayOptions to hide the guidelines.
Note: ◼You must call Update after changing colors ◼If a standard color, such as cl3DLight is used, it may be overridden by VCL theming colors. Set EnableTheming to false to prevent this
// Make control support theming IEColorCurve1.BackgroundColor := clWindow; IEColorCurve1.CurveColor := clWindowText; IEColorCurve1.GuidelineColor := cl3DLight; IEColorCurve1.Update();