Playing with the new Text Size - was on Standard - I selected Medium size, clicked Test and was a bit surprised to see the Properties notebook shrink in size. Is that supposed to happen?
Absolutely!
The size of dialog windows and their contents is proportional to the size of the default system font. IOW, a bigger font produces bigger dialogs. This worked great back in the days when all dialogs used the default font (System Proportional) for their text. As the font size increased, the dialogs automatically grew to accommodate. Then along came WarpSans...
To ensure that the system used the new font, eCS and AOS added entries to 'os2.ini' to force the use of 9pt WarpSans rather than the system default.. However, no one ever added an entry to lock down the default. I guess they assumed this was invariant and would always be 10pt System Proportional. But that isn't the case: at resolutions of 1280x1024 and above, the default system font changes to 12pt System Proportional. The result on higher res displays is overly-large dialogs that have been scaled to use 12pt while their content hasn't been scaled up and remains at 9pt.
'Text Size' addresses this by *always* setting the default system font to a size that will comfortably handle whatever size of WarpSans you choose. For the "Small" and "Medium" (9 and 10pt WarpSans) sizes, that's 10pt System Proportional. The result is dialogs that are the "correct" size - in this case, smaller.