Spidified cluster changes the size of the blue area overlay

[danzel]

1. Zoom in close to a cluster that will be spidified and hover over it to see the blue area
2. Click on the cluster to spidify
3. Hover over the (opaque) cluster behind the spidified map tags

The blue area in 3. is not the same size as the blue area in 1.

Reported by @ajbeaven

[danzel]

I'll take a look and see how easy it is to make the area behave correctly in this case.
If it is difficult we'll just not show the area when spiderfied.