Date label disapears when date field is part of a vertical tab

I have the same issue.
Date 7.x-2.0-alpha4
Drupal 7.7

When placing the date field in a vertical tab group, we lose all fieldsets.

This appears to be a bug in core css: http://drupal.org/node/1015798

I am using seven as the admin theme, so I have created a seven subtheme and added the css from the patch on http://drupal.org/node/1015798#comment-3952034

div.vertical-tabs .vertical-tabs-panes fieldset fieldset {
  border: 1px solid #ccc;
  margin: 1em 0;
  padding: 2.5em 0 0;
}
div.vertical-tabs .vertical-tabs-panes fieldset fieldset legend {
  display: inline-block;
}

This fixes it for us.

This also happens when using Field Collection.

[EDIT] Well it may be different. I don't see a label to even theme.

<div id="edit-field-position-collection-und-0-field-position-dates-und-0-value" class="date-padding">
  <div class="form-item form-type-textfield form-item-field-position-collection-und-0-field-position-dates-und-0-value-date">
    <div class="date-date">
      <input id="edit-field-position-collection-und-0-field-position-dates-und-0-value-date" class="date-clear form-text" type="text" maxlength="128" size="60" value="07/01/1991" name="field_position_collection[und][0][field_position_dates][und][0][value][date]">
    </div>
    <div class="description"> Format: 09/27/2011</div>
  </div>
</div>

Subscribe.

It looks pretty ugly as part of a vertical tab group too, image attached.

Bug is still present in alpha5. I can reproduce the problem two ways:

1. "Start Date" and "End Date" labels don't show up, but the surrounding fieldset's (the node field label) does. (Not nested in any other groups)
2. Dates placed inside vertical tab groups have missing labels.

#1 solved it for me

div.vertical-tabs .vertical-tabs-panes fieldset fieldset legend {
  display: inline-block;
}

The title of this issue was mis-leading, this is a vertical tab issue not a field group issue (as in the field group module). #1 indicates this is a core bug, so I don't see that there is anything Date can do.

I'm not sure why you'd mark it as fixed?

Assigning over to Drupal core.

There is already a core issue, referenced above. There is no need to create another. This is 'fixed' from the perspective of Date, as in there is nothing for Date to do. If it makes you happier I'll mark it Won't fix.

Sorry to open again, but I don't think the core fix addresses the problem - the styling of a date field is totally inconsistant with the other form elements. See the attached image ... what do you think - maybe we can do better?