Product and version: FileMaker Pro 14.0.x
OS and version: OSX 10.10.5
Description: Fill color on dropdown calendar button has holes when the field has a radius on the corner. Especially pronounced when a field outline is added.
How to replicate:
Add a date field to layout with dropdown calendar button.
Set date field fill color
Set calendar button fill color to a different color than the date field
Add some radius to the right side corners
Add on outline to the date field that is the same color as the calendar button fill
If the date field has a transparent fill you can place an object of similar color under the calendar button to hide the problem.
If the date field fill is not transparent there is no workaround.