Is collateral reserved on an open order or only after execution?
eg. If you trusted 4 different assets (eg. USD, CNY, EUR and AUD) and wanted to short all your btsx ie. go "All-In", could you post the same valued short against all of the 4 assets? Then once one executes, the other 3 disappear or cancel?
If not (which I get the feeling is the case), a feature suggestion maybe to short to "the markets you tick the checkbox for". ie. One short-wall order for different assets.