Annotations not working, not even in Dygraphs' own example on jsFiddle, why?

I'm currently trying out Dygraphs (which seems really great btw!), but for some strange reason, the annotations feature won't work for me, AND it also fails in the exact same way on the jsFiddle version of Dygraphs' own gallery example of annotations, so this is most likely a bug/problem the devs really might want to take a look at(!).

To reproduce (same thing happens in both latest Firefox and latest Chrome):

1. Look at the "annotations" example in the Dygraphs gallery, here: http://dygraphs.com/gallery/#g/annotations It works just fine and looks great, like this:

2. Press the "Edit in jsFiddle" button, for that very example on that very page. You are now sent to jsFiddle, and if you press the "Run" button there, the chart itself (colored curves etc) is shown just fine, but, only the "stems" of the annotation "signs" are shown, while the text contents of the annotations are all displayed as normal text to the left of the chart?! Like this:

Seems like some kind of CSS problem or similar to me, am I correct?

Since the example is Dygraphs' own example, which also works on their own site but not on jsFiddle, all suspicions of incorrectly formatted data or code can also be let go, I guess. It also happens to all my own Dygraphs charts on my own computer that I try to annotate, but this native Dygraphs gallery example is a much better example to investigate from I guess?

So, my question is of course, why does this happen, and how do I fix it to get the annotations working and displaying correctly?

ADDITION:

Let's make it even simpler, in order to isolate the problem without any hesitation.

Here is a very simple example for Dygraph annotations that I have put together on my own local disk (i.e. as a stand-alone HTML file):

<html>
<head>
<script type="text/javascript" src="dygraph.js"></script>
<link rel="stylesheet" src="dygraph.css" />
</head>
<body>
<div id="test_chart" style="width:750px; height:350px;"></div>

<script type="text/javascript">
  var test_annotations = [
    {
      series: "TestCol1",
      x: "2017-05-26",
      shortText: "A",
      text: "Test annotation",
      cssClass: 'annotation'
    }
  ];

  testchart = new Dygraph(
    document.getElementById('test_chart'),
    "Date,TestCol1\n" +
    "2017-05-25,110\n" +
    "2017-05-26,80\n" +
    "2017-05-27,75\n",
    {}
  );
  testchart.setAnnotations(test_annotations);
</script>
</body>
</html>

When I open this file (locally with file:// in Chrome on my computer, having the latest dygraph.js and dygraph.css in the same directory), this is what I get:

As you can see, exactly the same problem as described above appears here, i.e. only the "stem" of the test annotation is visible in the graph itself, while the annotation text ("A") is displayed to the left of the graph.

The Firebug console is empty after having loaded this file, and no attempts (unsuccessful or otherwise) of loading any images are anywhere to be found in the Firebug network tab either.

Again, this very much feels like some kind of CSS positioning problem to me, but I may of course very well be wrong?

The answer to provide to this question would then be:

How, in as few and simple changes/steps as possible, would I get this local example PoC code for Dygraphs annotations to work as intended, i.e. showing the annotation text "A" inside a square at the correct position inside the graph (i.e. at the position where the "annotation stem" is currently just displayed, just as is done in the working example on the Dygraphs page, in my first screendump above in this question)?

Solution

It seems that I was right about the CSS positioning problem after all.

The annotations are rendered by Dygraphs by adding the following HTML to the DOM of the page (this is the exact HTML for my test annotation in my local example code in the question test above, extracted live using Firebug):

<div style="font-size: 14px; left: 392.5px; top: 241.214px; width: 16px; height: 16px; color: rgb(0, 128, 128); border-color: rgb(0, 128, 128);" class="dygraph-annotation dygraphDefaultAnnotation dygraph-default-annotation annotation" title="Test annotation">A</div>

If I (as suggested by this SO question) add the CSS property position: relative to this div (manually, using Firebug), the graph suddenly looks like this:

See, the annotation text is now correctly positioned! It's still missing its opaque background and colored border though, but I guess this is just the result of even more CSS properties missing for some reason?

So, let's focus then on why there is missing CSS for the annotations I guess?

My best guess is that the dygraph.css file isn't properly loaded under certain conditions (apparently both on jsFiddle and locally on my computer, even though it is indeed there in the same directory as the HTML file and dygraph.js)? Or am I wrong?

A Firebug dump of the applied CSS for the annotation div seems to support this. Here is the CSS from Firebug for the annotation div of my local example (and also same in jsFiddle):

And here is the CSS for the same thing in the working instance in the gallery on the Dygraphs site:

See, the classes from dygraph.css is completely missing in my local example and in the jsFiddle example (even though indeed explicitly referenced in the class attribute of the annotation div's html code, as can be seen above), even though the CSS file is indeed there in the same directory as the dygraph.js file?!

@danvk, do you have any idea why this happens, and if Dygraphs could be patched somehow to avoid this from happening, and thus load all the CSS that it is supposed to for the annotations?

The only working hack-solution I can find for the moment is to dump the entire contents of dygraph.css inline in the <head> of the HTML file, as so:

<style>
/**
 * Default styles for the dygraphs charting library.
 */

.dygraph-legend {
  position: absolute;
  font-size: 14px;
  z-index: 10;
  width: 250px;  /* labelsDivWidth */
  /*
  dygraphs determines these based on the presence of chart labels.
  It might make more sense to create a wrapper div around the chart proper.
  top: 0px;
  right: 2px;
  */
  background: white;
  line-height: normal;
  text-align: left;
  overflow: hidden;
}

...

/* For y2-axis label */
.dygraph-label-rotate-right {
  text-align: center;
  /* See http://caniuse.com/#feat=transforms2d */
  transform: rotate(-90deg);
  -webkit-transform: rotate(-90deg);
  -moz-transform: rotate(-90deg);
  -o-transform: rotate(-90deg);
  -ms-transform: rotate(-90deg);
}
</style>

After that it's finally working fine:

Addition:

It seems like others too (1) (2) have this general problem regarding the loading of CSS files. No accepted answer to neither that SO question nor Mozilla support thread though, and indeed, none of the suggested answers work for me either. WTF, how can such a huge problem be generally unknown/unanswered? Please do also note that the same thing happens for me in both Chrome and Firefox, and also on multiple computers, out of which some have never opened the file before, so no strange cache-related effects should be involved either. Either way, it would seem like the bug is outside of Dygraphs' scope.