Hello @ric ,
I was finally able to reproduce the issue that you had and indeed it was an edge case scenario. I can have the steps to reproduce here:
- Step 1. Load the page and go into the columns section and hide all the columns that has date or datetime field
- Step 2. Now refresh the page
- Step 3. Go to the “Filters” button and try searching by this field. You can see that now the field is unstyled.
To be honest, I haven’t even thought that this is possible 
In short, because Grocery CRUD is loading the third-party libraries such as React datepicker only if it is loaded just to not have a full load of CSS without the actual need.
As a work-around, as you said you can either click add or edit form or unhide the date field from the datagrid.
I will try to fix this issue for the next release. Thank you for pointing that out. I will keep you updated on this one.
Regards
Johnny