[trac import 8/9/14 by flavour] Double-clicking on Baselayer gives odd results

[devinbalkind]

If a Base layer in the Layer Tree is double-clicked then no base layer is visible.
To make the base layer visible, need to select an alternate base layer (single-click) & then single-click again on the desired layer.

[tcarney14]

Layer also disappears with a single click of Layer name text.

In https://github.com/sahana/eden/blob/master/static/scripts/S3/s3.gis.js, a comment on line 852 says

// Extend LayerNodeUI to not force a folder with Radio buttons to have one active
// - so opening folder doesn't open first layer
// - so we can deselect a layer

I am curious why we might want this to be the case. Why would we want to view the map without a base layer?

[flavour]

We use Radio buttons for some Overlay folders...helps users avoid combinations which don't make sense