Limit the tickers we can trade - Feature

For example, I would only like to trade micros. But I often select the mini / regular size contracts instead. This can quickly blow up account. Request a feature to prevent that from happening by having a predefined list of tickers I can choose from. There should be a toggle button for this feature. If switched on it says on until the user toggles if off. When toggled on the platform should show the user a blank list. Then the user can add the tickers they want to trade, i.e. only micros. From now on the user can only select tickers from that list not from the regular search bar. Users can edit the list i.e. add or delete tickers, as they please.