Problem in generation of class (mixing + classes)

[mamcx]

I have this mixin:

.button_icon (@img) {
   background-image: url(@img);
}

And this classes:

.save {
  .button_icon("../static/img/icons/icon_save.png");
}

.delete {
   .button_icon("../static/img/icons/icon_delete.png");
}

But when the css is builded, the "delete" class is generated with the info of the "save". So, delete is generated as:

.delete{
  .button_icon("../static/img/icons/icon_save.png");
}

[cloudhead]

I think this was fixed a while ago. If not, please re-open issue.