This commit replaces a block of jQuery code that I believe does nothing. I found it while starting the work to make our JS code compatible with jQuery 3 as it uses jQuery.fn.keyup() which has been deprecated.
As far as I can understand, this block of code is supposed to change the focus to the coupon description when the user hits the tab key while the focus is on the title field. It doesn't work because the keyup event is not fired for the tab key. The current behavior is that when the user hits the tab key, the focus changes to the "Generate coupon code" button, and if the tab key is pressed another time, the focus changes to the description text field. Which seems fine to me and that is why I'm suggesting we remove this code instead of fixing it.
I believe it was added in this c15b8e817c commit six years ago and unfortunatelly the commit doesn't provide much information on why it was added.
For bulk edit: even if stock status was left as "No change", the
status of all variations was being changed to whatever the status
of the product was before it was converted to variable. Now
no change is performed when "No change" is selected, and all
variations change to whatever is selected otherwise.
For quick edit: a new "No change" option is added that will be
preselected when the product is variable. Previously, whatever
status the product had before being converted to variable was being
shown, and that's the status that would be set when saving.
Also, a "This will change the stock status of all variations"
message is displayed before the selector.
The serializeJSON function was causing a long delay when preparing the JSON if there are many input fields within the variations (even worse if 3rd party plugins add their own extra fields there too).
The default value ('no') of the setting to round taxes at subtotal was not being honored on the Edit Order screen, which resulted in off-by-one discrepancies between the checkout item total and the edited or refunded item total.
This change is to round to the proper precision (w.r.t. the 'woocommerce_tax_round_at_subtotal' setting) for the default value of the form, as well as when the values are dynamically recomputed.