property Chart.ShowTransparentBars as Long
Gets or sets a value that indicates percent of the transparency to display the bars.

TypeDescription
Long A Long expression, from 0 to 100, that indicates the percent of transparency that's used to paint the bars. 0 means opaque, 100 means hidden, or 100% transparent. 50 means semi-transparent.
By default, the ShowTransparentBars property is 0, which means that the bars are opaque. Use the ShowTransparentBars property to draw all bars using a semi-transparent color. Use the ShowTransparentBars property to draw the intersection of bars using a semi-transparent color. 

The following screen shot shows only few items that are shown using a semi-transparent color ( the bars in red ). Use the ItemBar(exBarTransparent) property to specify the percent of the transparency to display a specified bar. Use the ItemBar(exBarOffset) property to specify the the vertical offset to show the bar.

The following screen shot shows two bars when the ShowTransparentBars property is 0:

The following screen shot shows two bars when the ShowTransparentBars property is 60, which means 60% transparent: