Dojo Tooltip only shows after first mousover event - dojo

Question

I'm using dojo's event delegation to connect a Tooltip widget to dynamically generated dom nodes.
The Dojo site explains event delegation this way:
"The idea behind event delegation is that instead of attaching a
listener to an event on each individual node of interest, you attach a
single listener to a node at a higher level, which will check the
target of events it catches to see whether they bubbled from an actual
node of interest; if so, the handler's logic will be performed."
Following is my code implementation. It works beautifully ... EXCEPT, the tooltip only shows AFTER the first mouse over event. When I first mouseover the node, the event fires perfectly, but the tooltip doesn't render. It will only show the consequent mouseover events. On the first mouseover event, I can watch the Firebug console and see the xhr.get go to the database and get the correct data. If I comment out the tooltip and throw in a simple alert(), it works the first time.
Any suggestions on how to get the Tooltip to show on the first mouseover event? Thanks in advance!
<div class="col_section" id="my_groups">
<div class="col_section_label">My Groups</div>
<ul>
<?php
foreach($myGroups as $grp) {
echo '<li><a class="myGroupLink" id="grp'.$grp['grp_id'].'">'.$grp['name'].'</a></li>';
}
?>
</ul>
</div>
<script>
require(["dojo/on",
"dojo/dom",
"dijit/Tooltip",
"dojo/_base/xhr",
"ready!"], function(on, dom, Tooltip, xhr) {
// Get Group ToolTip
var myObject = {
id: "myObject",
onMouseover: function(evt){
var grp_id = this.id;
var content = '';
xhr.get({
url: "getGrpInfo.php",
handleAs: "json",
content: {
grp_id: grp_id,
content: "tooltip"
},
load: function(info) {
if(info == 0) {
content = '<div class="grpToolTip">';
content += ' Information about this group is confidential';
content += '</div>';
} else {
content = '<div class="grpToolTip">';
content += ' <img src="../ajax/getimg.php?id='+info.logo_id+'" />';
content += ' <div style="text-align:center">'+info.name+'</div>';
content += '</div>';
}
new Tooltip({
connectId: [grp_id],
label: content
});
},
error: function() {}
});
}
};
var div = dom.byId("my_groups");
on(div,".myGroupLink:mouseover",myObject.onMouseover);
});
</script>

Answer 1

Your Tooltip does not show on the first onmouseover because it does not exist at the moment the onmouseover event was fired.
dijit/Tooltip instances manage theirs mouse events themselves, so you do not have to manage onmouseover/onmouseout and you probably did so because you do not want to preload data or you want to load data every time the tooltip is about to show.
Beside dijit/Tooltip instances you can use Tooltip.show(innerHTML, aroundNode, position) and Tooltip.hide(aroundNode) to display tooltips, but in that case you will have to manage mouse events yourself, which is what you need, because from the UX perspective, you do not want to show single tooltip, you want to:
Show a tooltip indicating information is being loaded.
Then either:
display XHR loaded information if a user still hover over the node
cancel XHR and hide tooltip on mouseout
Here is working example: http://jsfiddle.net/phusick/3hmds/
require([
"dojo/dom",
"dojo/on",
"dojo/_base/xhr",
"dijit/Tooltip",
"dojo/domReady!"
], function(
dom,
on,
xhr,
Tooltip
) {
on(dom.byId("groups"), ".group-link:mouseover", function(e) {
var target = e.target;
Tooltip.show("Loading...", target);
var def = xhr.post({
url: "/echo/html/",
content: { html: target.textContent},
failOk: true,
load: function(data) {
Tooltip._masterTT.xhr = null;
Tooltip._masterTT.containerNode.innerHTML = data;
Tooltip._masterTT.domNode.width = "auto";
},
error: function(e) {
if (e.dojoType != "cancel") {
console.error(e);
}
}
});
Tooltip._masterTT.xhr = def;
});
on(dom.byId("groups"), ".group-link:mouseout", function(e) {
var target = e.target;
Tooltip.hide(target);
if (Tooltip._masterTT.xhr) {
Tooltip._masterTT.xhr.cancel();
}
});
});​

Answer 2

As usual, I was over-thinking the problem, focusing on event registration rather than on simply creating the tooltips when the page loads. So, it's really stupidly simple:
query for the nodes
iterate through them and create the tooltips pointing to each node.
var myGroupsList = query("a.myGroupLink"); // query nodes based on class
array.forEach(myGroupsList,function(entry,i){ // iterate through
var grp_id = entry.id;
var content = '';
xhr.get({ // get data via xhr.get
url: "getGrpInfo.php",
handleAs: "json",
content: {
grp_id: grp_id,
content: "tooltip"
},
load: function(info) {
if(info == 0) {
content = '<div class="grpToolTip">';
content += ' Information about this group is confidential';
content += '</div>';
} else {
content = '<div class="grpToolTip">';
content += ' <img src="../ajax/getimg.php?id='+info.logo_id+'" />';
content += ' <div style="text-align:center">'+info.name+'</div>';
content += '</div>';
}
new Tooltip({ // create tooltip
connectId: [entry.id],
label: content
});
},
error: function() {}
});
});