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