The good extension of LibreOffice is the tool Alternative dialog Find & Replace for Writer, that complements existing tool in LibreOffice
This is a tool that already existed in OpenOffice and it was only now set to LibreOffice. is very useful for search and replace paragraphs spaces and many other signs of texts, options that have no standard tool in LibreOffice.

To install, first download it in link of LibreOffice extensions. To install, go to the "Toolbar" of LibreOffice, "Tools", and "Extension Manager", click on "Add", find the downloaded file and give ok. Then just use. It's simple, complete and useful.
EXAMPLE: It can be used to remove excess paragraphs, in a selected text:
a) select option "Regular",
b) select option "Empty paragraph";
c) select "currente selection only";
d) click "Find" ;
e) then "Replace" or "Replace All"
Icon that appears in the toolbar of LibreOffice:

- Alternative dialog Find & Replace for Writer
Extension that adds many new features to Writer's find & replace function
Below some screenshots:
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Note: same topic in MageiaBrasil Forum