Gray Boxes in Text

[Writer_Girl]

I have a story (I didn't write it) and the formatting is really strange. I'm not sure why there are gray boxes inside the text. What are they and how do I get rid of them? I did notice that I can delete them like they were a space, but I'm hoping there might be an easier way since there are a lot of them.

[RoryOF]

These are non-breaking spaces. Select one of them, use /Edit /Find and Replace; the selected character should appear in the Find box (although not gray). Click on the Replace box and enter a space character, then press Replace all.

If you leave them alone, they will not print as gray boxes, merely as spaces. You can hide them by clicking on /View /Field shadings.

[Zizi64]

Please upload a real ODF type sample file here.

The "boxes" probably are non breaking spaces or fields with a whitespace content, or other objects like the "list bullets with whitespace content"...
We can not examine them on a picture...

[Writer_Girl]

I've never heard of a non-breaking space before. Thank you for your quick help.
The find and replace fixed everything! What a relief.

But now I have a related question. If I wanted to insert a non-breaking space, how would I do that? I figure it would be good to know how to add them as well as delete them.

I will upload the Open Office file next time I have a question.

[Zizi64]

Shift-Ctrl-SPACE

[Zizi64]

The non breaking spaces will not be to resized when the paragraph will be adjusted as "Justified". For example between the engineering units and the numeric values like
12.34 °C (where normal space character means the non breaking space) looks better than the justified white spaces:
12.34___°C (the underline characters mean the justified - resized - normal whitespace character)

[RoryOF]

You can also insert them using /Insert /Formatting mark