I have the problem that my changes to the display style of cells doesn't save with the notebook. When I convert a cell to text-display and check before saving I can see that the style is set as text-display. When I save and reopen the notebook, the cell is back to being an inputform Display. Is there a way to save these cell styles so I won't have to change all the styles every time I open the notebook?
I have tried this myself and have a partial solution.
It seems that the Style of the cell overrides the display properties. So, if the cell's Style is set to "Input", then the display will revert to Input Form.
The partial solution is then to set the Style of the cell to "Text". That way, the display remains as Text Display.
One downside is that the font style is different between Input Style + Text Display, and Text Style + Text Display. The former has a serif font, while the later is sans serif. Also, it doesn't resolve the original issue of why the display should revert in the first place.