Updated to version 4.4.6. English.
In earlier version when editing formulas the cell references where shown in colour. This feature is not working in the updated version.
I have tried Tools > Options > LibreOffice Calc > View > Show references in colour
Forget this one. The problem was on one sheet of one spreadsheet only. On other spreadsheets the cell references are shown in colour when editing formulas. Sorry to have wasted your time. Thanks.