[OpenLayers-Users] How to use control OpenLayers.Control.Measure

[Vu Hong Thuan]

Hi all,
I add OpenLayers.Control.Measure to the map, but I can't see any
button which allows to measure.

        var measure=new OpenLayers.Control.Measure();
        map.addControl(measure);
        measure.activate();

Have you ever used  OpenLayers.Control.Measure? Any suggestion?