Several click controls. Should a layer be added to the map before you can add a control?

Question

This code works fine as it is, but it seems to depend on which layers are added to the map before adding controls. Is this always the case, or am I doing something wrong?

var highlightCtrl = new OpenLayers.Control.SelectFeature([a,b], { hover: true, highlightOnly: true, renderIntent: "temporary", eventListeners: { featurehighlighted: make_popup, featureunhighlighted: kill_popup } }); var selectControl = new OpenLayers.Control.SelectFeature([a,b,c,d], { clickout: true, toggle: false, multiple: false, hover: false }); map.addLayer(a); map.addLayer(b); map.addLayer(c); map.addLayer(d); map.addControl(highlightCtrl); map.addControl(selectControl); highlightCtrl.activate(); selectControl.activate(); 

Answer 1

No, it does not depend on adding layers to the map before adding controls. As you can see from in this example . You can add a SelectFeature control and activate it before adding a layer to the map.

corresponding code snippet:

 var selectControl = new OpenLayers.Control.SelectFeature(vectorLayer, { hover: false, highlightOnly: false, toggle: false, renderIntent: "select" }); map.addControl(selectControl); selectControl.activate(); map.addLayer(vectorLayer); //<-- layer added at the end