As far as I understand there are two options on how to handle cash when shorting stocks: .set_shortcash() False and True, where one adds the cash received from shorting and the other subtracts it. Isn't the real word behaviour of retail brokers such as IBKR to lock in the cash to the position? So when I open a short position on IBKR cash is neither added nor subtracted but maintenance margin is raised ? Would it be possible to add a third option to introduce this behaviour?

Im working on a pair trading strategy that iterates over a list of stocks.

I would like to only plot the spread between the pairs of stocks and not all their price series.

I would also like to plot the buy and sell symbols on the spread series, is that possible?

Thank you