Alternate spacing behavior
First of all, thank you for creating and maintaining this very useful control!
I've been looking for a WrapPanel implementation that automatically spaces its children to fill the available space and this is working like a charm.
However I would appreciate an option to disable the spacing at the start and end of each row/column.
Here are two screenshots to illustrate what I mean:
The first one portrays the current behavior, which adds the same spacing on either side that's used between each item.
The second one is my slightly altered version, which only adds the space between items, so the outer edges are flush with my search box.
For now I simply override the ArrangeOverride method.
It's a relatively minor change, the only catch would be the behavior when there is only one item per row;
not sure if you'd want it to left-align, center or stretch in that case.