A field can be made so small that it is unseen.
A field can have no borders or fill and text is colored the same as the background
A field can have huge font size so nothing appears.
A merge text entry <<Merge Text Field>> can be empty until filled. Or text color changed to red from background color.
Hiding Something on the Layout
Hidden portal trick: conditional field
Miscellaneous behavior changes in FileMaker Pro 12
Are there any behavioral changes in FileMaker Pro 12 compared to the prior version?
Answer ID: 10084Last Updated: May 16, 2012
Unstored calculation field evaluation changed
Some customer solutions assume that an unstored calculation field will be evaluated when a layout containing the field loads, even when that field is completely hidden by other layout objects.
To improve performance, FileMaker Pro 12 will generally NOT evaluate an unstored calculation field that is completely hidden on a layout. Similarly, if the unstored calculation field's result never needs to be drawn (e.g., due to field width or height of 1-2 pixels) or is never needed for conditional formatting or another calculation, the unstored calculation will never be evaluated.
An unstored calculation field is evaluated at least once if that field's text (or a calculation dependent on it) is displayed on a layout.
Use 2 different layouts, one without the field and one with the field. Your button switches layouts as needed.
Here's a demo file that illustrates a number of methods for hiding layout objects--including fields: https://www.dropbox.com/s/8levaz6deiyzjr8/LayoutObjectVisibilityControlDemo.fp7
One of the tricks in this file uses conditonal formatting to hide a field with visible borders...
thanks very much for the responses... I'll work through these and find the best method for my solution...