Unfortunately your contact form doesn't work (says mailserver down), so let me add some feature suggestion here:

1. Multi selection.
While holding CTRL it is possible to make multiple non-contiguous text selections (either by dragging the mouse or double clicking on words for example). Would it be possible to search for each of these selections automatically and highlight them in different colors? This would be very useful if you'd want to see where certain selections appear close to each other again on a page.

2. Trigger highlight by context menu
I usually select text with my mouse so the keyboard shortcut is a bit "far away" (and I don't want to have highlight activated all the time). Would it be possible to add a context menu entry to trigger the highlighting?

3. Keep the highlight even if the selection is reset
It would also be nice if the highlight could be kept active until either a new selection is made or highlight is made by the context menu added in 2, depending on how the highlight was triggered.