Color leakage in OneCategoryLayout

[trixon]

When having a OneCategoryLayout on a custom WorkbenchFX style I'm getting two unwanted artifacts.

1. The purple row where the undo/redo buttons are.
2. A thin purple box around all the settings. (ok, the background, not a box)
   

By replacing

PreferencesFX/preferencesfx/src/main/java/com/dlsc/preferencesfx/view/PreferencesFxView.java

Line 74 in d09c87b

public void layoutParts() {

with

    public void layoutParts() {
        // but always add the categoryController
        contentBox.getChildren().addAll(breadCrumbView, categoryController);
        VBox.setVgrow(categoryController, Priority.ALWAYS);

        preferencesPane.setDetailSide(Side.LEFT);
        preferencesPane.setDetailNode(navigationView);
        preferencesPane.setMasterNode(contentBox);
        preferencesPane.setShowDetailNode(!model.isOneCategoryLayout());
        setCenter(preferencesPane);
    }

I get the wanted result.