Staff label unable condensing

How can i make dorico condense two players (oboe) in a page even if the 2nd has recently changed from the Eng Horn?
The software maintains two separate staffs because in the first bar of the page the label “Ob” (after the change) is displayed.

You would (I believe) have to make Oboe 2 your principal instrument for the Oboe/Eng Horn Player and then add the English Horn to the Player as the second instrument, since only the principal instrument for each player can be condensed.

yes, it is already so, the problem is that the “statement” of label change happens on the first bar of the new page.

Can you post an image of the problem area?

in the firs page there is the first label “prendere…” but then the label “ob” is just at the beginning of the second and this is why oboes do not condense there.

I don’t think your diagnosis is completely right, @gies.andreas. When Dorico changes instruments, it does so at the next barline immediately following the last note in the old instrument, so Dorico is definitely showing the oboe 2 staff at the start of the new page. If you could attach a part of your project that reproduces the problem, I’d be happy to take a look and see if I can figure out what’s up.