[OpenLayers-Users] Having problems with custom mouse event handlers

[Nick Whitelegg]

Hello everyone,

I am trying to develop custom mouse event handling code so that when the user 
drags on the map in a particular mode, the distance corresponding to the drag 
is calculated and displayed. The mouse down handling code is something like 
this:

function mouseDownHandler(e)
{

    if(mode==3)
    {
        dragging=true;
        return false;
    }
    else
        map.controls[0].defaultMouseDown(e);

    // Four attempts at preventing the drag and drop thing happening
    e.preventDefault();
    document.onselectstart = function () { return false; }
    Event.stop(e);
    return false;
}

In other words, if the mode is 3, my custom code kicks in, otherwise the 
default mouse handling code is called, resulting in the map moving in 
response to a drag.

The problem is this. Despite attempting four different ways of preventing it, 
the e.preventDefault() and return false (which I was aware of before 
OpenLayers) and the onselectstart and Event.stop (which I found by examining 
the OpenLayers code), I can't prevent the "drag and drop" action occurring 
(Firefox 1.5 on Linux). This has the knock on effect of  preventing a mouse 
up event being registered when the user stops dragging/

Can anyone give any guidance as to what I'm doing wrong here? Previously to 
prevent the "drag and drop" thing happening, the simple "return false" has 
worked.

Full code at http://nick.dev.openstreetmap.org/openlayers/main.js

Thanks,
Nick