Placeholders for Empty Elements: -oxy-placeholder-content Property
Used to configure placeholders for empty elements.
Oxygen XML Author Eclipse plugin displays the element name as pseudo-content for empty elements if the
        Show placeholders
          for empty elements option is selected in the
        Author preferences page and there is no before or after
      content set in the CSS for this type of element. There are two CSS properties that can be used
      to control the placeholders (-oxy-placeholder-content and
        -oxy-show-placeholder).
-oxy-placeholder-content CSS Property
      
      To control the displayed pseudo-content for empty elements, you can use the
          -oxy-placeholder-content CSS property.
The following example would change the 
      <keyword> element to be displayed as
          key:keyword{
    -oxy-placeholder-content:"key";
}Note: 
    This CSS property accepts the ${i18n(key)} localization editor variable, as in the
        following
        example:
-oxy-placeholder-content:"${i18n(id)}";-oxy-show-placeholder CSS Property
      
      The 
    -oxy-show-placeholder property allows you to decide whether or not the
        placeholder will be shown. The possible values are:- always - Always display placeholders.
- default - Always display placeholders if before or after content is not set in the CSS.
- inherit - The placeholders are displayed according to the Show placeholders for empty elements option (if before and after content is not declared).
- no - Never display placeholders.
Note: 
  Deprecated properties 
show-placeholder and
        placeholder-content are also supported.