Description:
In simple documents it works ok

But I have example document for you, in which change to text angle in table cell either doesn't save, either doesn't load to/from file (I don't know, maybe both)

I attaching two screenshots 
1. How I need text to be saved/loaded. this one taken right after save
2. How document looks after it's reload
and example document 'test.odt'

Steps to Reproduce:
1.select middle cell in example document
2.press right button and choose 'table properties'
3.go to 'text flow' tab 
4.select 'vertical (bottom to top)'
5.press ok
6.shrink middle cell to good looking size (I don't know if this step takes part in problem)
7.save document
8.close document
9.load document

Actual Results:
after reloading, text in middle cell looks as normal text and without normal angle

Expected Results:
angle of text in cell should be saved and loaded from file ok


Reproducible: Always


User Profile Reset: Yes


OpenGL enabled: Yes

Additional Info:
Version: 6.3.4.2.0+
Build ID: 6.3.4.2-2.fc31
CPU threads: 2; OS: Linux 5.5; UI render: default; VCL: gtk3; 
Locale: en-US (en_US.UTF-8); UI-Language: en-US
Calc: threaded