Good news today. I finally got the search function working in the Vindaloo PDF reader. I'm quite excited that I managed to implement it like Firefox does. The user enters some text in the find textfield and after a short delay of 250 milliseconds the search starts. No need to press a find button. When the contents of the textfield change, the search is automatically restarted. The delay prevents the search to be restarted just after each letter of a word. 250 milliseconds is the upper bound for what a user usually experiences as "immediatly". The best is that all this works reasonably fast and the user interface keeps responsive (at least responsive enough). The whole thing still needs some work but I think I'm out of the woods today.