This feature (among others) is in my production code base at https://github.com/braathwaate/frontac24 in the wwh branch.   By searching for "ajax sync" in the commits you could find some of the changes.  I admit this is confusing.  I made changes under other commit names, so you won't find everything this way.

One improvement was adding a nocache parameter to the core page() function.  The inquiry functions set this, so that after a return to the inquiry page after an edit, the page refreshes and shows the updated transaction, still using the same search parameters originally set by the user.

The original pull request is out-of-date.  As stated therein, many pages would benefit from the concept, and not all was implemented at that time.   There have been other bug fixes and improvements to it.

1) Click Sales Quotation Inquiry
2) Change the from Date to a past date.
3) Click the edit pencil
4) Click the Back or browser Back arrow

The result is I am presented with Search all Orders Screen which is not expected. I was expecting back to Sales Quotation Inquiry.

Is this a bug?

However, for the record, the back link in FA calls javascript history.go(), which is identical to the browser back button (see, https://www.w3schools.com/jsref/met_his_back.asp).

Thus, both techniques are open to exactly the same browser cache issue (will the back button display the cached page or will it refresh it?).   I haven't run into this issue with FA, as it seems to always refresh the page in my testing.  If it doesn't, a coder can force it to refresh using cache-control.

The pull request is a standard AJAX coding approach, nothing more (see, https://webmasters.stackexchange.com/questions/88790/how-should-the-back-button-behave-when-a-site-is-built-with-ajax-and-javascript). 

Finally, Web user interface design recommendations discourage placing a back link on a page if it duplicates the browser back button (page clutter).  If it does not duplicate the browser back button, then then link should be called something else.

The alternative would be to temporarily change the transaction days value to a figure that would generate the desired starting date from now.

@joe: can we code it to use cookies to store the various date ranges in screen inquiry forms?

This functionality has now been integrated into FA 2.4.x with the settings in the users table as the fields:

sticky_doc_date
transaction_days
save_report_selections

Make sure that the browser cache is cleared and the company's js_cache is also cleared. Logout and login again and see what gives. In the last case above, this user choice data are stored in cookies and you must have it enabled. The others store it in the session.

The function date_cells() is the one that sets the form element. There appears to be no mention of sticky_doc_date(), new_doc_date(), etc there to remember the dates. The _last_val attribute of the date cell should be set from the sticky value.

@joe: needs a check to extend it to search forms as well?

i checked the Remember last document date option in the preferences but it doesn't seem to be working.

other inquires and reports work just fine.