I agree your initial response, user can resize application window whatever he want, then the size is kept.
You can set the size using external program, but force a size to all users may be another trouble.
The only option that I can think of is to use a different layout for the larger monitors. A script can check screen size to determine if the current user has a large monitor and then select an alternate layout customized for the larger monitor size.
Yeah, I came to the same conclusion. I was hoping there might be a trick that would limit how far an auto-resize field would stretch. It would be nice if there was a max width value.
THere are a number of ways that auto-size anchors could be improved. That would be one. Another would be the ability to group objects, specify opposing anchors and see the group of objects correctly resize as a group to fit the window size.
You might search the Product Ideas section and vote in favor of any ideas that suggest the above and then create your own if no such idea is found there.