When you do Ctrl-F, it can pick up the current selection to search for that easily. (I'd like it to ignore "unit" but that's separate).
When you do Shift-Ctrl-F to find globally, it doesn't do the same. It would be nice if it did... At the moment you have to select, copy, Shift-Ctrl-F, then paste. The hardship. But I have been doing it a lot, and it is actually sometimes faster to Ctrl-F, Ctrl-C, Escape, Shift-Ctrl-F, Ctrl-V.