private void graphTabControl_SelectedIndexChanged(object sender, EventArgs e)
{
if (handler != null)
{
if (graphTabControl.SelectedIndex == 1)
{
// if preview tab has been selected, trigger export
ImageExportToPreview();
int i = ((TabControl)sender).SelectedIndex;
focusedCanvas = i == 1 ? previewCanvas : graphControl;
focusedCanvas.Focus();
}
}
}