In Vi-mode, if you search by, say using the shortcut ctrl + f, while the search box is open, pressing ctrl + f again while the search box is still opened causes the search box to disappear. Once the editor goes into this state, you can never get the search box back until you reopen the editor. I selected Version=16.04.1, but I'm actually using 16.08. Reproducible: Always Steps to Reproduce: 1. Search by using the menu or ctrl + f. 2. Search again without closing the search box by repeating step 1 once. 3. Any further attempts to search fails to bring up the search box. Actual Results: You can never get the search box back once you trigger the bug.
Here is some patch offer, but cant' say if it's sufficient or make things event worse https://phabricator.kde.org/D19408
I have started a merge request that fixes this bug https://invent.kde.org/frameworks/ktexteditor/-/merge_requests/40/ For now, a workaround to make the search bar show again is to try opening the command bar twice (by pressing ":" twice), then pressing Ctrl+F or "/".
> https://invent.kde.org/frameworks/ktexteditor/-/merge_requests/40/ The MR has just been merged. Hopefully it solves the problem for all cases and do not introduce new bugs.