There are two problems around o.n.m.e.lib2.highlighting.TextSearchHighlighting, the first is a potential race condition
with OffsetsBag, the second is need to recalculate highlights after changes. (Found this doing jVi's search highlight).

== race condition with OffsetsBag ==
Given following after search for "foo" all lines are highlighted
foo
foo foo
foo
foo
Select and delete the second line, the highlight of the third and fourth line disappear. This can be traced to
    public void removeUpdate(DocumentEvent e) {
        this.bag.removeHighlights(e.getOffset() - 1, e.getOffset() + e.getLength() - 1, false);
    }
Both the bag and TextSearchHighlighting respond to the removeUpdate and too many highlights are affected. There are two
issues I think
1) listener race condition. Maybe a bag should have an "addDocumentListener" so it can forward the event after it does
its thing, or have other versions of HighlightChangeEvent that embeds the document event. (NOTE: the code adds the
listeners in the "right" order and comments on it, but the java Document API says "order of delivery is not guaranteed".)
2) Assuming the bag goes first, its not obvious from the documentation what action the hightlighting should take. In
OffsetsBag, there no mention of behavior after doc mods. In particular, what should be done if a hightlighted area is
completely removed? There's a comment in AbstractGapOffset, "The offsets inside the removal area will be moved to its
begining.", so are there a bunch of zero length highlights left laying around? In any case, on a removeUpdate
e.getLength() should never be used for determining bag.removeHighlights()

== recalculate highlights after change ==
Continuing with the initial example, and assuming the first problem is fixed, if you delete some lines and then undo,
the re-inserted lines are not highlighted. Or if I add a new line with "foo" on it, shouldn't it be highlighted. Note
that fixing this, takes care of the first problem.

I solved this problem in jVi by adding "fillInTheBag(startOffset, endOffset, replaceAll)" method, and use it from the
document listeners. jVi sets startOffset and endOffset so complete lines around the change are recalculated; done for
both remove and insert. FYI, the replaceAll flag is used like
                    if(replaceAll) {
                        bag.setHighlights(newBag);
                    } else {
                        int bug = -1;
                        bag.removeHighlights(startOffset, endOffset+bug, false);
                        bag.addAllHighlights(newBag.getHighlights(startOffset,
                                                                  endOffset));
                    }

BTW, newBag.discard() is never called in TextSearchHighlighting