I'm using LibreOffice Writer to write a novel and the line-spacing is all messed up. Single, 1.5, double-spacing all on the same page.
There is nothing intrinsically wrong with that, of course: in another circumstance, you might well want such variation - even on a single page.
I've tried Format-spacing, Windows-paragraph and everything else -- but nothing works.
I don't recognise "Format-spacing" or "Windows-paragraph", but no matter.
What looks like double spacing may actually be single-line paragraphs interspersed with empty paragraphs. You can see if this is the case by modifying the text: does it flow naturally from line to line? In addition, go to View | Non-printing Characters (or the Non-printing Characters button in the Formatting toolbar, or press Ctrl+F10). This will show the paragraph and line breaks, if any.
Line spacing within a paragraph is a paragraph property as well as a paragraph style property, and what you see may be the result of either. Right-click in the paragraph and go to Paragraph... | Indents & Spacing | Line spacing. Is the rogue spacing set there? Now instead right-click in the paragraph and go to Edit Paragraph Style... | Indents & Spacing | Line spacing. Is the rogue spacing set there? Select your choice from the options in the drop-down menus.
The best way to control such properties is by using paragraph styles, but note that local paragraph formatting will override this. You may want to select all your material and use Format | Default Formatting to clear local formatting before applying styles or seeing their effect.
Different situations may apply to different parts of your page, of course. If you have inherited any of this material from elsewhere or have pasted it in yourself, there are other possibilities - but if you are writing a novel I very much hope that this is not the case!
Incidentally, don't worry unduly about formatting if you are currently *writing* your novel. Surely you will want to edit the text as you review your work, so you will want the formatting to be appropriate for your own on-screen reading? You can apply appropriate formatting later, when you are close to completing your work and contemplating printing it.
I trust this helps.
Brian Barker