Positioning of 'se' with participles

Question

First off, a minor suggestion wrt this lesson to break the ice: ;)

When you are talking about the position of 'se', you are in fact referring to the position of BOTH 'se' and a corresponding direct object pronoun. You might want to note this in the explanations somewhere.

Now, my real question:

With a participle, does the combo of se & direct object pronoun HAVE to be attached at the end, or this is just an option? "Se la estamos decorando" and "Estamos decorandosela" are both grammatically correct and semantically equivalent, right? Or are we allowed to say "Se la estamos decorando" only because we have two verbs next to each other?

PS

I agree with the other poster who pointed out that these agglutination rules totally warrant a separate lesson.

Answer

Hola Krimp
We've reworded the lesson so it refers to the position of both the se pronoun and the direct object pronouns too to avoid confusion. 
Both options of placements are equally correct and with the same meaning: You can either say: "se la estamos decorando" or "estamos decorándosela". 
There is a separate lesson that explains this more directly: 
Position of Spanish direct and indirect object pronouns with infinitive/present participle and affirmative commands
I hope this helps.
Saludos cordiales
Inma