This is because all versions of LibreOffice 25.2 have been compiled without the item, which is available in:
Menu ---> Tools ---> Options ---> Advanced —> Open Expert Settings:
org.openoffice.Office.Draw
misc
TextObject
TextObject ShowBoundary boolean true
And the only way to add it is by compiling the packages with a patch that includes that option.
This option appears in development versions 25.8.
If you want to install it:
To do this, open a terminal and:
To remove the version of LibreOffice packaged by the operating system developers and PPA, run the following command in a terminal:
sudo apt remove --purge libreoffice*
sudo apt update
sudo apt install --reinstall wget
sudo apt autoremove
sudo apt clean
Then, to download the packages for the latest development version of LibreOffice, run the following command in the terminal:
cd ~/Downloads
wget https://ftp.nluug.nl/office/libreoffice/libreoffice/testing/25.8.0/deb/x86_64/LibreOfficeDev_25.8.0.0.beta1_Linux_x86-64_deb.tar.gz
wget https://ftp.nluug.nl/office/libreoffice/libreoffice/testing/25.8.0/deb/x86_64/LibreOfficeDev_25.8.0.0.beta1_Linux_x86-64_deb_helppack_en-GB.tar.gz
wget https://ftp.nluug.nl/office/libreoffice/libreoffice/testing/25.8.0/deb/x86_64/LibreOfficeDev_25.8.0.0.beta1_Linux_x86-64_deb_langpack_en-GB.tar.gz
Once the packages have been downloaded, to install them, run the following in the same terminal:
for x in *.tar.gz; do tar xfv $x; done
sudo dpkg -i LibreOfficeDev_*/DEBS/*.deb
Once the final version is available in the PPA, you will need to uninstall this test version and install the one from the PPA.