That is a sign that the control is being instantiated small, then resized larger, forcing a font size resize that will distort the chart. The chart should be instantiated at the size of its initial display on the form.
In the XBarSigmaChart constructor make sure you call this.Dock = DockStyle.Fill before you initialize the chart, as the code below, extracted from the TimeVariableControlCharts.XBarSigmaChart example.
public XBarSigmaChart()
{
// This call is required by the Windows.Forms Form Designer.
// TODO: Add any initialization after the InitForm call
InitializeComponent();
// Have the chart fill parent client area
this.Dock = DockStyle.Fill;
// Define and draw chart
InitializeChart();
}
Double click on the XBarSigmaChart user control in the Solution Explorer of your project to display the control in design mode. Resize it to be approximately the size it should appear at runtime in your program. If either, or both of these suggestions fail to work, there is something else wrong with your project. You will have to send us the complete project as a zip file so that we can debug it. Make sure you remove everything in the example not associated with the chart.