I have searched the forums and the tracker, but I have not found this exact problem anywhere.
In Moodle 2.7.2 and Firefox (not in Chrome / I.E not tested)
I have a passage of text. In this text I want to insert a link with the link-button. This works fine for the first link. Then when I select a second textpassage and press the link-button again it contains the first inserted Url. I can insert the new url but this url then will be applied to the first selected textpassage, the second selected textpassage stays unlinked.
Something similar happens when I insert an equation with the equation-editor.
The first insert goes fine, but when I open the equation-editor again to insert a second equation it often contains the first equation and I can only change that one and not insert a second one in a different part of the text.
This makes it almost impossible to insert links or equations in atto in firefox. It seems to work fine in Chrome, I have not tested it in Internetexplorer.
Can you confirm this behavior? If so, it should be entered as a bug in the tracker.