Hi,
with the following code you can reproduce the bug. Add an empty file and type
addr.sin
addr.sin1
addr.sin2
then mark addr.sin with the mouse and then call the Find dialog using Crtl+F or Search->Find. The content addr.sin is put in the find dialog, but if you press now F3 you will get no search results.
If you mark addr.sin again with the mouse and use again Ctrl+F and then F3 you will get the correct search results.
The strange thing is, If you use the option Find uses selected Text the Search with Find Ctrl+F and F3 works properly.
Bye,
Mario