Label chart widget

Iam using label chart graph. Chart type is "line". I passed 3 infotable values to label chart widget of Datasource1, Datasource2, Datasource3. But it is displaying only the graph with values of Datasource1. If only Datasource1 passed, it is showing graph. If only Datasource2 or Datasource3 passed, no graph is displaying. What is the mistake here.