Eclipse syntax coloring plugin

I need to develop an Eclipse plugin that can "color" the same occurrence of a variable/value/tag in XML as the JAVA editor does.
I'm using the default XML Editor from eclipse, and am currently able to put a grey background on the selected words with the following code :

for (Point p : offsets){
        TextPresentation t = new TextPresentation();

        t.replaceStyleRange(new StyleRange( (int)p.getX(),
                (int)(p.getY() - p.getX()),
                null,
                Color.win32_new(null, 0xDDDDDD)));

        fText.changeTextPresentation(t, true);
    }

My problem is that I can't recover the default style if the user tries to select another variable/tag/value. The text will not set its natural coloring after loosing the focus. For the moment, I am using hard-coded RGB values to set the defaults colors, BUT it is only "working" if the user kept the Eclipse default theme (white theme).

Is there a way to ask the document for a complete syntax coloring re-validation ?

Thanks for reading.

I found an answer by myself. Here it is :

before changing the style of the selection, you should first save the current style. Use a similar structure:

private ArrayList<Point> offsets = new ArrayList<Point>();
private ArrayList<Color> foregroundgColor = new ArrayList<Color>();

Then you put all the styles/offsets of the occurences in this structure, in a loop statement :

offsets.add(new Point(i,j));    
fgColor.add(fText.getTextWidget().getStyleRangeAtOffset(i).foreground);

You can now apply the "highlighting" (grey background on the occurences) :

for (Point p : offsets){
        TextPresentation t = new TextPresentation();

        t.replaceStyleRange(new StyleRange( (int)p.getX(),
                (int)(p.getY() - p.getX()),
                null,
                Color.win32_new(null, 0xDDDDDD)));

        fText.changeTextPresentation(t, true);
    }

Finally, when the selected occurences loses the focus, you restore the default styles :

for (int i = 0; i < offsets.size(); i++){

            Point p = offsets.get(i);

            TextPresentation t = new TextPresentation();
            t.replaceStyleRange(new StyleRange( (int)p.getX(),
                                                (int)(p.getY() - p.getX()),
                                                fgColor.get(i),
                                                null));
            fText.changeTextPresentation(t, true);
        }

    offsets.clear();
    fgColor.clear();