my text does not react to mouse

I was writing my book, and suddenly, when I was deleting one part of the text, and transferring a copy pasted text to the other location, my text stopped to react to the mouse completely. When I checked the headline of my book in the files, there is two blue arrows, like describing some kind of process, I guess. How can I at least SAVE my previous writings, when the file is not reacting to anything I do?

Did you preset? :

LibreOffice internal

LibreOffice offers via the menu Tools>Options>Load/Save as ″ Save ″ the possibility to save the auto recovery information every “X minutes” (“X” stands for the number of minutes). LibreOffice uses the auto recovery info to recover a file after a crash.
A check mark can also be placed there ″ Always make backup copy ″. This saves the previously saved version of the document in a copy with the extension .bak when you save a document. The next time it is saved, it will be overwritten by the next status. This is a measure that is mainly used so that you can go back to an earlier version if you made mistakes when editing a document.
Backup copies are stored in the directory that is set under Tools>Options>LibreOffice>Paths for backup copies. On Windows 10, the backup copies are in the directory by default
C: \ Users \ USERNAME \ AppData \ Roaming \ LibreOffice \ 4 \ user \ backup

Or did you copy your file yourself beforehand? :

Simple file duplication

In the simplest case, you create a copy of the created file. However, if it is on the same data carrier as the original, both versions of the file can be lost if the data carrier is defective. So it makes sense to save a copy of the important files on an external data medium.

Can you cover any case? :

Residual risk

You have already noticed that there is always a small residual risk, but it is very low if the data is saved correctly. Surely you will not initiate the data backup after every word written, but think about what can be restored with a little effort.