MetaTrader 4 help: Charts Customization
Setup
Appearance and properties of each chart in the terminal can be set up individually. To do so, one has to execute the "Charts – Properties..." menu command, the chart context menu command of the same name, or press F8. These actions result in appearing of the "Properties" window that can be used for setting of the color of various elements of the chart (the "Colors") tab:
Background – chart background color;
For