Fixing old pre-1.6.1 themes

[DaveDavenport]

In 1.6.1 we split the element into element-text and element-icon (see 1.6.1 release notes).

To make an old theme work add the following section to the theme file:

element-text {
    background-color: inherit;
    text-color:       inherit;
}

[DaveDavenport]

If you use icons, you might want to add:

element-text, element-icon {
    background-color: inherit;
    text-color:       inherit;
}

instead.