since updating to v8 (or 8.01, can't remember when it started to happen), the colors for the default Darkula theme don't always work correctly. I do not have any customizations to the theme, just using the theme as is.
Here's a screenshot of the preferences pane:
Note the color of the methods (i.e., $this->invent).
Now here's a screenshot of the editor:
Note that the methods are all in white, rather than in orange like it shows in the preferences.