Ok so I store the pending in one of my remaining TradeVar slots. Easy enough.

As TradeVar are only available from loop(all_trades/open_trades) and TMF this points to 2 possibilities
1) All plot functions are called within a TMF which just doesn't sound right and you could end up with inconsistent series (out-of-sync plot calls)
2) Loop over open_trades and create a series of the pending bar to be passed back to plotGraph

#2 seems to make more sense for how I understand zorro but seems (computationally) wasteful.

There is no fixed delay between when trades are placed and when they are opened and I think this will cause issues for LINE.
For example, say a pending trade (trade1) is placed @ bar1 but is not filled until bar20. Another trade (trade2) is placed at bar10 and is not filled until bar30. Won't LINE connect the pending bar of trade2 to the open bar of trade1 as it connects the 'last position to the current position'.

I have to admit that besides pointers/memory functions, graphing functions are by far my weakest toolset. I really struggle with them in R. MQL4, not so bad. But I also haven't one anything to interesting on that front

Cheers,
BobbyT