Below is the text from a tableau kb as is. On that basis, I understood that Tableau might try to adapt to different window size.
The dashboard scales within the specified minimum and maxium sizes. If the window size is outside the range, scroll bars appear on smaller sizes, or white space is added to larger sizes.
Thanks for the reply. But this is not a case of not understanding how "range" works. Ive used it plenty of times before. Its quite obvious that my published dash is a "fixed" size. Furthermore, when i choose "Range" using tableau desktop and put in my min and max values, then if i navigate to another tab and back it has switched itself to "automatic" (although still shows my min and max values). This is definitely new behavior for 9.3.