Elastic Objects in WrapPanel

I want to put a few charts on a markup page. Some could be wide, some could be square. If I put these in a WrapPanel object, then as many that will fit in a row as possible will, and the rest will automatically move to the next row.

This is nice, and working as expected.

However, what would be nicer:

Is there was a way to stretch a child object of the WrapPanel to the full width of the panel if it is the only object on the row (the next object wrapped to the next line because it wouldn't fit), but squish it down to >=MinimumWidth if the next object will fit.

So instead of ending up with this:



We get this:



Thanks in advance for any tips.