> On 24 Feb 2022, at 22:10, Xavier B. via ntg-context <ntg-context@ntg.nl> wrote:
> 
> Even if I change 
> \startexercici[exercici:operacions-amb-fraccions-2]{multiplicació i divisió} Opereu:
> \startitemize[a, columns, three]
> 
> 
> for
> 
> \startexercici[exercici:operacions-amb-fraccions-2]{multiplicació i divisió} Opereu:
> \startitemize[a, columns]
> 
> 
> the 'c' jumps.
> 
> Isn't ConTeXt capable of handle that?

Please see the attached PDF which is your sample with the command \showmakeup[vbox] added after \starttext

The green line shows how much space is needed to fully print item (b).  Item (c) will need the same amount of space, shown by the red line. However, this would take you into the footer area (shown by the blue arrows), so item (c) is split: the item label fits into the space at the bottom of the column and so is printed there; the fraction doesn't fit and so is moved to the next column.

We can confirm this theory by setting the footer to nothing with the command \setuplayout[footer=0mm] and then the columns are as you wish. However that only works for this example and the situation would inevitably arise again.

The solution to your problem would be some way of forcing the item body to stay with the label. I don't know what that command is - hopefully someone here can tell us.

—
Bruce Horrocks
Hampshire, UK