# Bug in anchor mouseup?

**URL:** <https://discourse.mozilla.org/t/bug-in-anchor-mouseup/87730>\
**Category:** Firefox Development\
**Created:** [October 26, 2021, 4:58pm UTC](https://discourse.mozilla.org/t/bug-in-anchor-mouseup/87730 "2021-10-26T16:58:08Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Diamanti](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Diamanti](https://discourse.mozilla.org/u/Diamanti)\
**Post date:** [October 26, 2021, 4:58pm UTC](https://discourse.mozilla.org/t/bug-in-anchor-mouseup/87730/1 "2021-10-26T16:58:08Z")

</div>

In Firefox 9.40b1, in this example, after a few of click over the link “Click me” the link move from right to left and the have strange attribute:  
linkhref=“null”  
linkstyle=“float: right; margin-right: 10px;”  
Same problem with Seamonkey 2.53.  
No problem with Chrome and Edge.

```
<!DOCTYPE html>
<html><head>
<meta charset="utf-8">
<title>TEST</title>
</head>
<body></body>
<script>
"use strict";
var a=document.createElement("div");
a.id="main";
document.body.appendChild(a);
var res=document.createElement("div");
res.id="res";
a.appendChild(res);
var an=document.createElement("a");
an.textContent="Click me";
an.style.float="right";
an.style.marginRight="10px";
an.addEventListener("mouseup", e=>{
	e.preventDefault();
	e.stopPropagation();
	if(e.button===0){
		var a=document.getElementById("last");
		a.innerHTML="new";
		a.previousSibling.firstChild.textContent=new Date();
	}
}, false);
res.insertBefore(an, res.firstChild);
a=document.createElement("div");
a.textContent="test";
a.id="last";
res.appendChild(a);
</script>
</html>
```

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<div class="post-metadata">

**Author:** ![jscher2000](https://sea1.discourse-cdn.com/flex001/user_avatar/discourse.mozilla.org/jscher2000/32/28202_2.png) [@jscher2000](https://discourse.mozilla.org/u/jscher2000)\
**Post date:** [October 27, 2021, 3:50pm UTC](https://discourse.mozilla.org/t/bug-in-anchor-mouseup/87730/2 "2021-10-27T15:50:51Z")

</div>

I am not seeing that in Firefox Developer Edition 94.0b9 (latest release, I think).

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<div class="post-metadata">

**Author:** ![Diamanti](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Diamanti](https://discourse.mozilla.org/u/Diamanti)\
**Post date:** [October 27, 2021, 3:58pm UTC](https://discourse.mozilla.org/t/bug-in-anchor-mouseup/87730/3 "2021-10-27T15:58:34Z")

</div>

I updated to Firefox Developer Edition 94.0b9 but I see still the problem.

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<div class="post-metadata">

**Author:** ![jscher2000](https://sea1.discourse-cdn.com/flex001/user_avatar/discourse.mozilla.org/jscher2000/32/28202_2.png) [@jscher2000](https://discourse.mozilla.org/u/jscher2000)\
**Post date:** [October 29, 2021, 6:34am UTC](https://discourse.mozilla.org/t/bug-in-anchor-mouseup/87730/4 "2021-10-29T06:34:46Z")

</div>

Can you rule out extensions as a possible culprit? [https://support.mozilla.org/kb/diagnose-firefox-issues-using-troubleshoot-mode](https://support.mozilla.org/kb/diagnose-firefox-issues-using-troubleshoot-mode)
