Created attachment 126063 [details]
See Additinal Information for image discription.

SUMMARY
5.18.0 update messed up LibreOffice window decorations and removed Menubar unless in full screen mode.

STEPS TO REPRODUCE
1. Open any LibreOffice application.
2. 
3. 

OBSERVED RESULT
LibreOffice application opens without Menubar and with lower portion of screen (under footer) containing portion of screen under window.


EXPECTED RESULT
LibreOffice application opens normally with Menubar and footer on bottom of window where it belongs.


SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.18
KDE Plasma Version: 5.18.0
KDE Frameworks Version: 5.67.0
Qt Version: 5.13.2
Kernel Version: 5.3.0-28-generic
OS Type: 64-bit

ADDITIONAL INFORMATION
If I make window fullscreen using KDE's menu icon on the left of the Titlebar, the menu shows up, however if I use SHIFT-CTL-J to do so, there is no Menubar shown.  Also with SHIFT-CTL-J, when the other toolbars are displayed, the messed up portion under the footer is present, whereas with the header menu fullscreen mode it is not.

Attatched image contains two screenshots.  Top one taken with 'Window Under Cursor' which shows borked portion of screen on top of window above titlebar and unknown transparent window border (colored pink by me for clarity), second is 'Rectangular Region' which shows borked portion under footer as I see it onscreen.