In Find (ctrl-f) or Replace (ctrl-h), we should be able to type a nonbreaking space or a nonbreaking hyphen into the Search For and Replace With fields. The only way to enter it in the Replace dialog's Search For field or in the Find dialog (ctrl-f) is by finding it manually, i.e., by eyeballing the file for the string, selecting it, and opening either dialog. Then, if desired, it can be copied from the Search For field and copied into the Replace With field. This is too cumbersome. Bug 87525 is related. So is Bug 89573. I uninstalled and reinstalled Writer on Aug. 16, 2015, and got a different user interface look, but still received only version 4.3.7.2, even though that was not offered via LibreOffice.org a few minutes later, so apparently that version is still being supported. If the problem still applies to a later version, addressing that will be enough. My hardware is AMD.
You need to use regular expressions: https://help.libreoffice.org/Common/List_of_Regular_Expressions Help reference: https://help.libreoffice.org/Writer/Using_Wildcards_in_Text_Searches For non-breaking space you should search \u00A0 From https://en.wikipedia.org/wiki/Hyphen#In_computing, for non-breaking hyphen you should search for \u2011 Another method: use the Altsearch extension (http://extensions.libreoffice.org/extension-center/alternative-dialog-find-replace-for-writer). This extension seems to not work with LO 5 but works well with previous versions (until LO 4.4). Best regards. JBF
Good point. This is too obscure or rare to call for a way without using regex, which I forgot about. I'm closing.