I don't have access to my Mac at the moment to see if this is platform specific or not, so I thought I'd post it here--feel free to move it if it belongs elsewhere.
There seems to be no way--beyond the preferences--to specify a flex or exact search in Search All. (In contrast to a "normal" search in a specific text, where this is chosen from the magnifying glass icon) Is this by design, or is this a bug?
This also creates a bit of confusion when double-clicking on a translation in the list on the left of a Search All Window: When searching the specific translation, the search is run as an exact search.
As a specific example, When my preferences were set to Flex in Edit>Preferences>Search Tabs, I used Search all Texts to search for "first love" (without the quotes) Although I had intended an exact search, it ran as a flex search.
When I select NIV in the translations list, several verses were displayed, only one of which used the phrase "first love"; the rest used "first" and "love" somewhere in the verse.
I then double-clicked on NIV in the translations list, which opened an NIV pane and ran an exact search. So only the exact search showed. This really confused me at first: several hits in Search All, only one in the translation search.