Commodity market Error loading

[Globule]

I have the following problem reported on the startup screen:
"The commodity market from expansion pack was not loaded because it requires oolite.oxp.spara.market_observer witch is not installed"
How to solve this problem?

thank you

[Venator Dha]

Commodity market requires another OXZ called Market Observer. Download this from the expansion pack list and then it should work.
Did you download Commodity market from the expansion pack list in the game or from the wiki? As if from the expansion pack list it should have downloaded the other OXZs it required?
Edit: strikethrough misleading info

[spara]

Assuming you're playing with Oolite 1.80, Commodity Markets requires Market Observer to work. So you need to install that. It does not get installed automatically. Automatic installation of required OXPs is a feature of the current development version of Oolite, which is not recommended for actual playing.

[Globule]

Thank you for your answers, in fact I was missing "market observer".
thank you very much