****** I'm not looking at the program now and maybe my being blind will help you see.
"All works fine when the window is created without the resize flag set."
***** Am I correct that the resize flag is a bit about the window type that tells whether you can resize the window by dragging the bottom corner and also makes the green button appear which acts in concert. I have some intuitive feel that The resize box in os 9.x gets information from the drags on the lower right hand corner, not the interface standard, but rather some particular smarts in particular programs.
"... I try to resize the window to the smallest size, there is a difference (12 pixels) between the size of the window obtained with goSmall and the size of the window obtained by dragging the bottom right corner. "
***** The smallest and largest size with the go methods was from the views. There is also a smallest and largest size from inspector that can be slaved to the view, I believe, by the springs. I recall inside and outside springs, but don't recall whether that was in the windows or the views. Those are bits that can be fiddled with and the column suggested some experimentation with the words like "set springs as appropriate".
"It seems that the goSmall method overrides the resizing mechanism, not taking into account the 12 pixels right border needed to draw the resize flag."
***** Now that I have tried to actively respond to each of your paragraphs, I finally understand what you are saying. That phenomenon in my brain is very interesting! Could you put conditional code (say in an if statement) in that notes the size of the resize flag (which I suppose is the way things are written : you identify the bit with the drag place that appears or does not appear depending on whether that bit is set). I had a similar experience where a window dissappeared because the size of an mp3 window size was zero and then I put in a condition don't resize it to that window size. What is going on when we both thought we were doing something wrong was we thought something should have been afforded by an automatic mechanism of Apple, a confusion of responsiblity whose distinction (ours from Apple's) requires a much deeper knowledge than we are ready for. Sort of exhilirating when you pull out of the "power dive" though.
***** I had a brilliant supervisor at Rockwell Space Division and when I came to him with problems he'd catch my discussion at critical places and simply say "Is that so?" Fritz Perls said that sometimes our flustered feelings of being confused disguise intelligence; maybe that has to do with the confusion of responsibility giving a fuzzy pointer to much deeper things.
***** Well, that's as good as it gets. Maybe now, I've given you some company and you will get that obvous hindsight and thank me for keeping you company as you had done me in my rebriefed experience above.