Esta é realmente parte do tema. Não é configurável através do gconf-editor. Aqui é um exemplo de como editar o XML de um tema arquivo.
Antes:
<draw_ops name="title-text-focused">
<title color="shade/#000000/0.8" x="0" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="1" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="2" y="(((height - title_height) / 2)+1)"/>
<title color="#f0f0f0" x="0" y="(height - title_height) / 2"/>
</draw_ops>
<draw_ops name="title-text-unfocused">
<title color="shade/#000000/0.8" x="0" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="1" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="2" y="(((height - title_height) / 2)+1)"/>
<title color="#808080" x="0" y="(height - title_height) / 2"/>
</draw_ops>
Depois:
<draw_ops name="title-text-focused">
<title color="shade/#000000/0.8" x="((3 'max' (width-title_width)) / 2)" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="((3 'max' (width-title_width)) / 2)" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="((3 'max' (width-title_width)) / 2)" y="(((height - title_height) / 2)+1)"/>
<title color="#f0f0f0" x="((3 'max' (width-title_width)) / 2)" y="(height - title_height) / 2"/>
</draw_ops>
<draw_ops name="title-text-unfocused">
<title color="shade/#000000/0.8" x="((3 'max' (width-title_width)) / 2)" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="((3 'max' (width-title_width)) / 2)" y="(((height - title_height) / 2)+1)"/>
<title color="shade/#000000/0.8" x="((3 'max' (width-title_width)) / 2)" y="(((height - title_height) / 2)+1)"/>
<title color="#808080" x="((3 'max' (width-title_width)) / 2)" y="(height - title_height) / 2"/>
</draw_ops>