Changing HighlightingStyle colors at runtime

I am attempting to change the ForeColor property of a highlighting style at runtime and it doesn't seem to change the text in the editor to the new color.

I basically do

foreach (HighlightingStyle style in editor.Language.HighlightingStyles)
{
style.ForeColor = getColor(style.Key);
}

However, the text in the editor stays the original color. Is there anything I have to do in addition to the above to make the style change occur?

Thanks