Rests in secondary voices

Hi,

I’ve been having some trouble with the notation of a bar’s rest in the first bar of a choral piece. See the attached screenshot. I’d like the bar’s rest in the second bass part to look like the whole bar rest in the upper parts, but it naturally is set as three crotchet rests. I have forced it into a dotted minim rest (as in the screenshot), but this looks odd to me too. If I press delete on the rest, it is deleted rather than returning to a whole-bar rest. Can you help?
Screen Shot 2017-03-01 at 12.52.21.png

You can input an explicit bar rest using the ‘Insert Bar Rest’ button in the Bars and Barlines panel on the right-hand side in Write mode.