How to create a format that shows empty cell regardless of content.

Hi, I would like to create a format that will show the cell as empty when set.

The use case is that I have a timesheet that has dates filled based on a single field. But I want cells to appear empty when date falls outside current month (for this I write a formula).

The first thing I tried was setting format to the empty string but it didn’t work. Then I have set format to "" and this now worked. I didn’t know formatting also has quoting. Leaving this here in case anybody else hit this question.

Either "" to display an empty string but only for numeric (and date,time,…) data and formula results, or ;;; for four empty subformats that covers also text content and text results. Which is the same as [>0]"";[<0]"";"";"" and loaded as such once saved to .ods