public void StartModify()
{
if (scroll && hist_len == 0)
{
throw new Exception("inv1 bug");
}
if (scroll)
{
TL_e = Hist[hist_pos].Copy(); // <- this destroys any temporary changes to TL_e that are not committed hist histroy via Enter
scroll = false;
} // else do nothing the line to modify already is TL_e
}
// TODO: hard limit on hist size
public void H_push(RenderableTokenLine TL)
{
Hist.Insert(0, TL.Copy());
}