this is a explanation why partial close has problems in basket type situation and not in a standard order situation
in a standard order situation, trailing is usually done by number of pips
in a basket situation, trailing has to be done by value (as the pips make no sense as 1 pip has a different value based on the currency pair)
therefore assuming you have trailing switched on to start trailing at 20 USD profit, trailing at 75%
once the basket reaches +20 USD it will set the minimum profit to 15 USD (75% of 20 USD)
this means that as soon as the total basket value drops below 15 USD the basket will be closed.
The basket profit keeps on going in our direction and now reaches 30 USD, therefore the minimum profit is now 22.50 USD.
At this point we activate partial close for half of the basket
Half of the basket is then closed, however the value of the basket is also then reduced by half, dropping the value of the basket down to 15 USD, which is less than the minimum profit of 22.50 USD and it will then assume that price has reversed and close out the other half.
This is where the logistical problems are, do we on partial close, also drop the minimum profit by the percentage closed (ie. 50% closed, drop the minimum profit by 50%, which could work, ie. Minimum profit would be set to 11.25 USD and wouldn't auto close, however it wouldn't start trailing that basket again until it reached the trailing value of 20 USD again, which might take a while as it is trying to do this with half of a basket - or do we also reduce the start trailing at value also by 50 %)
ie. a total logistical nightmare, with many opportunities for things to go wrong.
Incidentally - this happens currently - if you have a winning basket that is trailed and you close some of the profitable trades, the same can occur that the whole basket closes - though as i mentioned to me it only makes logical sense to close the losers, which won't cause total basket closure
in a standard order situation, trailing is usually done by number of pips
in a basket situation, trailing has to be done by value (as the pips make no sense as 1 pip has a different value based on the currency pair)
therefore assuming you have trailing switched on to start trailing at 20 USD profit, trailing at 75%
once the basket reaches +20 USD it will set the minimum profit to 15 USD (75% of 20 USD)
this means that as soon as the total basket value drops below 15 USD the basket will be closed.
The basket profit keeps on going in our direction and now reaches 30 USD, therefore the minimum profit is now 22.50 USD.
At this point we activate partial close for half of the basket
Half of the basket is then closed, however the value of the basket is also then reduced by half, dropping the value of the basket down to 15 USD, which is less than the minimum profit of 22.50 USD and it will then assume that price has reversed and close out the other half.
This is where the logistical problems are, do we on partial close, also drop the minimum profit by the percentage closed (ie. 50% closed, drop the minimum profit by 50%, which could work, ie. Minimum profit would be set to 11.25 USD and wouldn't auto close, however it wouldn't start trailing that basket again until it reached the trailing value of 20 USD again, which might take a while as it is trying to do this with half of a basket - or do we also reduce the start trailing at value also by 50 %)
ie. a total logistical nightmare, with many opportunities for things to go wrong.
Incidentally - this happens currently - if you have a winning basket that is trailed and you close some of the profitable trades, the same can occur that the whole basket closes - though as i mentioned to me it only makes logical sense to close the losers, which won't cause total basket closure