I have a column with customized data validation (custom formula) that accepts only dates, provided that a few other conditions are met.
How can I add a date picker to the cells of this column? Changing the Format did not help.
Edit: I want to pre-program my cells to have a date picker, just like they would have if the Data Validation criterion were set to Date.
A good workaround is provided by @user0, but I am still interested to know if this is directly possible.
Unfortunately, you can't. Date picker in Google Sheets is available only when a cell contains a valid date. Empty cells can be pre-programmed to offer you the date picker (via Data Validation), but not if you use a custom formula in Data Validation.
Your next best option is to have a chosen pre-programmed date, for example, like 1/1/1900 and have it hidden with white font color via Conditional Formatting. This way the date picker will be available in cells that look like they are empty until a different date is set.
