VBA Excel: setSourceData make Border around...?

[engine]

Hallo Experts,

ActiveChart.SetSourceData Source:=Range("A1:A5,B1:B5&quot
PlotBy:=xlColumns

After the two lines above, Visual Basic automatically draws
a border around the datas in the Excel tables which appear in the chart. Every time when I click on the chart, i can see the related datas (border around)

My problem:
ActiveChart.SetSourceData Source:=Union(Range("A1:A2&quot, _ Range("A4:A6&quot), PlotBy:=xlColumns

After these two lines above, VB no longer draws a border around the data Range in the Excel table (because the Range is discontiguous)
why and can this problem be solved?

Thanks everybody in advance!!!!