Howto identify modalForWindow using NSViewController - objective-c

Question

I have one NSWindow (mainwindow) for my OSX NSApplicationDelegate. The NSWindow also holds several NSView's where the content is set using NSViewControllers. Currently I ran into a problem when I wanted a NSPanel, a sheet, to drop down from the top of one of my NSViews (not from the top of my app). I wanted to use the code:
[NSApp beginSheet:self.loginSheet.window
modalForWindow:self.view.window
modalDelegate:self
didEndSelector:nil
contextInfo:nil];
The loginSheet is a subclass of NSWindowController which loads the xib file using:
loginSheet = [[sheetWindowController alloc] initWithWindowNibName:#"loginSheet"];
However, I run this code from my NSViewController and my self.view.window is always nil. My NSView seems otherwise correctly initialized and works fine, but the drop down of the sheet does not work as my modalForwindow (self.view.window) is nil. If I use the code:
[NSApp beginSheet:self.loginSheet.window
modalForWindow:[[NSApplication sharedApplication] mainWindow]
modalDelegate:self
didEndSelector:nil
contextInfo:nil];
it works like a charm. But from all my searching to find an answer to my problem it seems that this working approach is a big no-no since it blocks the entire app from any response. I wanted my sheet to be linked to one of my NSViews' but I dont see how I can do this given that the app only have one NSWindow? Am I not doing something that makes my self.view.window stay nil? Is there a good way for me to find the parent window of custom views? If you have any suggestions for how to solve this problem or can give me a hint on what I am doing wrong that would be greatly appreciated.
Thanks! Cheers, Trond

Answer 1

You should have a look at the "Positioning Sheets" section of "Introduction to Sheets" docs. It explains how to make a sheet appear from somewhere other then under the window's title bar using window:willPositionSheet:usingRect: