title: GTK background-full-height dosn't work
body: <p>I need your help, I'm trying to set background color on whole length of TextView.
  I'm trying to do it with this declaration: </p>
  
  <pre><code>gtk_text_buffer_create_tag(buffer, "white_bg", "background-full-height", TRUE, "background", "white","foreground", "blue", NULL);
  </code></pre>
  
  <p>And when I set text with:</p>
  
  <pre><code>  gtk_text_buffer_insert_with_tags_by_name(buffer, &amp;iter,"SAMPLE TEXT", -1, "white_bg", "left",  NULL);
  </code></pre>
  
  <p>It sets blue font, white background but it doesn't set white bg on whole length, only under text.</p>
  
  <p>Can You help me to figure out what am I doing wrong? </p>