How do I keep docked floating document windows the same size?

I don't use document tabs on the application frame (way too limiting), but do find tabs docked inside floating documents really useful. Especially as the window stays the same size to do direct comparisons and for easy tab browsing.

A recent update (maybe v.25 on MacOS?) has undone the same-size window feature, letting you resize an individual document's window when in a dock, which causes the floating document to jump to each resized window shape as you tab through. This make comparisons difficult, sometimes hides the remaining tabs, and loses its value as a useful, controllable container for those images.

Is there a setting to revert to the "before time" when resizing a docked set of windows meant it resized for all, instead of individually?