Hi,
I seem to remember that this has been discussed, but am unable to find it again. I find a bit strange that the tremolo symbols have been put among the ‘repeating structures’, instead of the ‘ornaments’. I feel them more logically related to trills, instead of alternative ending bars.
Is there a reason for this decision? Maybe it will be reconsidered?
Paolo
Dear Paolo,
This has been discussed ad nauseam in the early days of Dorico. It’s been considered that tremolo is a repeat of notes, which is also true.
This is probably going to be a waste of time and energy? In other words, it is as it is, move on 
One bonus of tremolos in the Repeats panel: to get a tremolo, you can type shift-R to invoke the Repeat pop-up, and then type a number: 3 for 3 tremolo strokes, 0 to cancel a tremolo, etc.
Of course you should use the R popover ! Add a 2 to the number of strokes for multinote tremolo (32, 22…). Make sure you’ve entered notes without ties (sometimes force duration is still compulsory) or these multinote tremolos won’t work.
Oh cool - I did not know about the multi-note tremolo shortcut, merci Marc!