Hi Kovid!
So, this is the text search box I'm talking about, with the "next" and "previous" buttons:
Step 1: Open up epub in ebook editor.
Step 2: type "x" in text search box (just a random character for testing), hit "previous", text box finds a "hit".
However, if I hit previous again, it just stays on that one hit. If I click "next", it'll go "forward" and find other cases of "x", but if I click "previous" again, it just stays on the most recent instance and doesn't go back to any of the previous instances of "x".
After playing with it extensively, it seems in my case it doesn't matter if I use "Saved Searches" or not, it's the same problem. And it's hit and miss, sometimes it'll work, other times it will not. I'm not doing anything different, the size of the epub doesn't seem to matter. It also doesn't matter if it's been converted or not.
Also, anything I typed for it to find when it does happen isn't saved in the text search saved memory. What I mean is, if I close the editor and reopen it, "x" doesn't show up on the pull-down menu even though I just looked for it.