Thank you for your post and I was happy to check this out for you.
I was able to reproduce your issue with windows adjustment in FileMaker Pro 14.0.5 on Mac OS X 10.10.5. I also found that FileMaker Pro 14.0.5 in Windows 7 Pro (64-bit) does not adjust window at all.
I will report my findings to Testing and Development. I will respond back here when further information is available.
Many thanks for your work.
Your workaround is interesting, however i think it will prevent the user to resize a window manually.
I did not found an efficient way to compare the Layout native dimensions with the capacity of the current Windows; for the latter, i use Get ( WindowsContentHeight ) and Get ( WindowsContentWidth ) but measuring the layout size is the problem.
Actually, i try to have always the same size for each layout and make an adjustment when the Show Hide Toolbar step is invoked.
All the best,