I have a question regarding the Calc settings. I want to have a view with headlines of columns and lines. I found the option to show the headlines. It worked but the programme didn’t save my choice of settings. Each time I open a file, the headlines disappear.
How can I make it a permanent choice or a default view?
Column/row headers Enabled is a document property, not a setting for the application. Spreadsheet documents saved without headers will thus re-open without headers even if you meanwhile changed the property for different documents. Newly created documents get the setting from the used template which is your ‘Standard’ template for Calc if not explicitly chosen (and the not editable ‘Default’ template if no standard template was created).
If you regarded all this, and documents saved with headers re-open without, a corrupted user profile might be the reason. See https://wiki.documentfoundation.org/UserProfile in this case.