fill outside rth vs allow pre-open....Difference?

Something Ive never quite figured out but need to figure out as Im trying to configure some limit order hotkeys for trading pre-post market.

What is the difference between fill outside rth vs allow pre-open? Doesn't "fill outside rth" also include the pre-market? The premarket is outside regular trading hours so why is there a seperate "allow pre-open" option?

When creating a hotkey it doesn't allow you to designate the either of these options. So you need to configure your order presets and you can only check one box or the other for fill outside rth vs allow pre-open.

Any clarification/help would be great. Thanks.

 

Pre-open excludes after-hours.

 

But does outside rth include pre-market?

Its weird to me there's a distinction

 

https://www.interactivebrokers.com/en/index.php?f=22063

 

Yes, outside rth includes both pre-market and after-hours.
You could use pre-market when placing orders at night for the next day but want to try to get a fill pre-market.

 

if you submit your trade as GTC...which of the 2 boxes below do you tick to have your order live ALL the time...regardless if after hours or pre-open?

ibkr only allows you to check one box

 

As it is it should do it, but just tick them both if possible.

 

it wont allow both