Bharat: I agree with you. And I disagree with you !

When I first realised that the X family of programming functions did not work in preview mode, I too considered it to be irksome to test. Then when I had to do extensive testing of XLookups, XUserSelect etc, I found it soon became quick and easy.
I've just done a test: ...
From Program Editor to open form in preview: 10 seconds.
From Program Editor, saving and closing layout, reconciling, and opening file and form in already-open Sesame: 17 seconds.
I think you'll find it's like so many things: it seems onerous at first, but once you are familiar with it you shrug and say "it's no big deal".
The hard part is
remembering that XLookups etc don't work in preview, when you are going backwards and forwards from program editor to preview mode trying to get that *£@#~ syntax working !