Due to the refactoring of the WinForm control by adding a picturebox in the FormsPlot user control the mouse events like OnMouseDown are no more forwarded like in the laste stable release.

A fix would be something like this

private void PictureBox1_MouseDown(object sender, MouseEventArgs e)
{
    Backend.MouseDown(GetInputState(e));
    base.OnMouseDown(e);
}

Or is it by intension to remove that?