When searching (with Ctrl+F), if the search key is not found, the text in the search box seems to be selected, with a red background colour. But it is actually not selected as typing a new search text does not overwrite the old one and just appends to it. This is inconvenient. If the search text is not found, it should be selected so that user can overwrite it with a new one. The current scheme is misleading as the rad background for the text makes it look like the text is selected.
I can confirm this behavior. Typing additional text will only append to the search term instead of overwriting it. This seems odd, because the color effect applied to the text makes it seem like the text is selected when it is not. CCing the UX team.
The design has changed for 24.2 and the input field does not change on enter. You may have a peek at the beta version https://de.libreoffice.org/download/download/?version=24.2.0 (if the link fails check at the bottom for the version). Whether a selection is needed depends rather on the next intended action than on the result. You may search for "Lorem" and fine-tune it to "Lorem ipsum" or you search first for "Lorem" and then exclusively for "ipsum". Either we always select the search key on enter to allow easy overwriting or never.
We discussed the topic in the design meeting. In most cases you don't want to overwrite all text in the search key but perhaps change one character. And if you want to overwrite ctrl+F does the trick with full selection right now. So we recommend to resolve this ticket as NAB.