In Mageia the width of a LibreOffice window cannot be smaller than the length of the menu bar.
To replicate, open a LO component and reduce the width of the window. It can be reduced to the full size of the menu (not tool) bar, but not farther. If resizing before LO has loaded completely it is possible, but as soon as the menu bar appears the window is resized to accommodate the bar.
Although I am reporting this for Mga6 with LO 184.108.40.206, this bug also appears in Cauldron with LO 220.127.116.11. As Mga6 is the current stable version, I gave it priority in reporting.
Expected behavior is that items on the menu bar will simply be covered over/disappear as the width is reduced. This is the behavior in: Windows (tested personally), a Debian-based liveUSB (tested personally), and has been reported by LO users to work in Linux Mint (LO 18.104.22.168, DE unknown) and Puppy (LO 22.214.171.124, DE unknown) and openSuse (126.96.36.199, LXDE).
I am running E21 in Mga6, E22 in Cauldron, both fully up to date.
Things that I have tried in Mageia:
1) Changing the theme: this problem appears with the Vertex and Adwaita themes (light and dark in both)
2) Removing the Spanish language pack: the problem appears with US English as well.
3) Changing DEs: the problem appears in IceWM Session as well, and in the Live version of Mageia XFCE.
These variations suggest that there is something amiss in Mageia, or at least in Mageia Gtk DEs as I have not tested with Plasma or LXQt.
For English language installations this is not much of a problem, but I have my systems set up in Spanish and added the Anaphareus extension to LO Writer. It adds itself to the menu bar and now prevents me from reducing window size below about 60% of the screen width. I suspect there may be other languages for this will be a problem as well.
Assigning to the registered maintainer.
Might be due to now using gtk+3
Also valid as of 188.8.131.52-1.fc27 on FC27
Please report it upstream at https://bugs.documentfoundation.org/ and add back the upstream bug ID here
Upstream bug report submitted: https://bugs.documentfoundation.org/show_bug.cgi?id=116290
Fixed upstream as of version 6.1.5 and confirmed in Cauldron 6.2.