Can you provide a screenshot of the issue please? 

Bonjour et merci voici le résultat (pièce jointe) et la formule utilisée

Bien cordialement 

IF(
{Mardi Activité Matin*},
DATETIME_FORMAT({Jour 3}, 'DD/MM/YY')
& " " & Mardi
& " - " & {Désignation Abrégé copy}
& " - " & {Mardi Activité Matin*}
& " - RDV : " & {Heure Rdv Mardi Matin*}
& " - Panneau : " & {Lieu RDV Mardi Matin*},
BLANK()
)

Thanks for the screenshot and the formula!  Hmm, could I confirm that in your formula field, you've created one option per possible outcome of the formula?

In the following screenshot, you can see that the second record does not display an option as I did not create a select option of "06/06/24 Mardi - Désignation Abrégé copy"

Hello and thank you for your feedback, I think that what I want to do is not in line with the formula

The formula for my field concatenates several results from several fields. I would like to color the "single selection" field = {Tuesday Morning Activity*}, this field has several possibilities: Mountaineering, climbing, hiking.... so it is one of these outings that I would like to color
IF(
{Tuesday Morning Activity*},
DATETIME_FORMAT({Day 3}, 'DD/MM/YY')
& " " & Tuesday = 06/17/24
& " - " & {Abbreviated designation copy} = PBS Mt Blanc
& " - " & {Tuesday Morning Activity*} = Day hike or climbing, or mountaineering or trail....
& " - Appointment: " & {Meeting time Tuesday Morning*}
& " - Sign: " & {Meeting location Tuesday Morning*},
BLANK()
)

The information that results from the formula
06/17/24 - PBS Mt Blanc - Day hike - Meeting: - Sign: , 06/17/24 - Brek PBS - Day hike - Meeting: - Sign:

Merci

Hmm, the formula field will only output single select options for options you've manually created, and so you will need to create one option per variation of the formula output

For example, if you have a formula that outputs "A", "B", "C", you must set up your formula field's select field options like this:

If not it will just display as "Default".  For example, if I make the formula field now output the text "D", it will show the option "Default" instead, does that make sense? 

Bonjour et merci, voici un lien vers d'une vue où j'ai reproduis ma problématique

sur les deux dernièrs champs de formule l'un est avec la mise en forme le second sans mise en forme 

champs "Calcul et mise en forme" avec le résultat avec mise en forme 

champs "Calcul sans mise en forme" avec  le resultat de la formule 

https://airtable.com/appYGvpIAdS7m5Hab/shrX4X3SSqiDnYRkU

Pour moi le réslutat que je recherche c'est :

bonne jounée

Yeap, it's because you did not create each possible output as an option in the single select field.  Once it's set up like this:

It'll look like this:

Link to base

Merci pour votre réponse cela est compliqué à mettre en place

Yeah, I don't think they expect it to be used with very dynamic formula outputs I'm afraid