Whenever I edit a layout it adds that new field to the tab order.... which isn't something I ever really want. There are only a few specific fields that I want users to be able to tab between and I keep getting odd user errors because of this.
Is there a way to make it so that new fields are NOT tab-able by default?
You are in luck there is a setting for that under Preferences. I wish by default it was off. In all my years of using FileMaker I have never wanted it on but many times have been annoyed it is on.
Here are the steps to turn it off.
@Susurrus I'm not sure this is what @JasonMark refers to (but I'm happy to be corrected if I am wrong).
I believe Jason is talking about layouts where he adds fields to the layout himself, but would like them not to be included in the tab order.
I do not know of a way to achieve this, but I am all ears if someone has a trick to suggest.
Yeah, I've never wanted that on either, but Bobino is right, what I'm looking for is a similar checkbox that says "Don't add new fields to tab order".
I was just excited to answer a question 
I am sad to report now that I understand the question I no longer have an answer for you.
And also, @Susurrus: Even if not what Jason was asking for, the tip you offered is a worthwhile one to be aware of.
I would even add that, at least, now that he has to add each new field to the layout, it might help to remember to delete the added tab. I find it very annoying as well. I wish we could modify or add to the interface the way I used to with Word. A bit of VBA and xml coding and you could add functionality to the ribbon to automate some processes.
Would love another tab in FM Prefs for these.
Filemaker Annoyances
I always want a header on my table views.
I used to always want GoToNextRecord to exit after last.
I never want to auto-add new fields to a layout.
I never want to add new fields to the tab order.
I almost always want a button to halt any current script.
I almost always want a cursor to appear over a button.
I never want a scripted Enter Find Mode to have pause on.
I never want a footer on a layout.
I get around most of that stuff with a text expander that can handle AppleScript and/or JavaScript.
Besides just handling some of the annoyances, it adds multiple script steps, already set with "defaults" I prefer. I do the same thing in almost any/all programming languages and code languages.
Can you share an example? Right now I:
I often lament having to go in an manually adjust tabs. This, for me, is particularly true of portal fields where I'm simply returning data from several given fields based on a single field in a portal record. Not sure if it's just me or a program issue in general, but trying to manually redo tabs sometimes (often?) crashes FM18.
Are you on windows? Can you reproduce the issue? In the latter case, I would say to report the bug to Claris. However, they will tell you to upgrade to 19 since many bugs in 18 were corrected in 19 and that it will eventually reach the end of support period.
Honestly, I haven't intentionally attempted to recreate the issue, but have noticed it many times. In most cases, I believe I have multiple windows open, and apparently tabs pushes it over the edge.