Affected Confluence Version: 6.11
Pre-requisite: Using Confluence with non-English language (reproduced with German)

Steps to reproduce:

1. Create a new Page, add an attachment, save Page
2. Hover over an Image (or another file preview) and drag&drop the "inline" comment icon
3. Notice how the "X" (close) button has dropped down below it's original place (b1.jpg)
4. Click on the comment and if you try to click the "..." icon, the "x" button will appear and block it (b2.jpg)

Workaround

Edit the CSS styling by shrinking the "x" button height & width as below :

<style type="text/css">
   .cp-container button.cp-icon {
		width:25px;
                 height:25px;
                 margin-bottom: 12px;
	}
</style>