Trouble Adding New First Measure + Pickup

I’m attempting to insert a new (3/4) first measure into an existing flow (no trouble) in Dorico Pro 4.2, and also to include a one-beat pickup to that first measure. The result: the first “full” measure has just two beats, compensating for the “stolen” beat of the pickup. This happens whether I use the right-side palette or a Shift-M entry of (“3/4,1”).

I’ve tried selecting the entire flow before adding the pickup, thinking it might then steal the beat from the final measure, but I get the same result.

What advice from the community?

Before inserting it, turn on Insert mode (I).

Alternatively, you can click inside that partial measure and use Shift-B, 1q, Enter to add one quarter note and complete the measure.

If you already had another time signature in the next bar, that will be why – Dorico won’t create extra beats before an existing time signature unless Insert mode is active (as Dan described above).