Start LibreOffice, go to Tools, select Options…, then go to View, check the box Use OpenGL for all rendering (on restart), close Libreoffice and start it again. This solved the issue for me.
If for any reason your system becomes slow(er) after you activate OpenGL and your computer has an AMD GPU (AMD Graphics Processing Unit), it is likely that your system is affected by this bug. In such case, see this comment for instructions on how to upgrade your Linux kernel to a more recent stable version.
Note: such kernel upgrade instructions apply to *Ubuntu (Ubuntu, XUbuntu, KUbuntu…) 16.04, only. They might be useful for Mint users, too, but if your system is older (e.g. 14.04) or if it’s a different distro (Arch, Fedora, Slackware…) then you’re still encouraged to upgrade your Linux kernel but the kernel upgrade steps will be different and you should look for help on your distro’s forum.