I would like to disable the animation that Cocoa performs when displaying a modal sheet.
Apple's Sheet Programming Guide states:
... Other sheet behavior, such as the animation when it appears and is dismissed, is handled automatically by the Application Kit.
But it doesn't provide any hints on how to disable this effect.
I have created a custom sheet (a subclass of NSWindow with a transparent background and some controls in it). I am able to display it using the standard beginSheet method as follows:
[NSApp beginSheet:myCustomSheet
modalForWindow:mainWindow
modalDelegate:self
didEndSelector:...];
The sheet displays fine, but it goes through an animation when it appears, and again when it closes.
Note: I am writing a completely customized user interface for a touch screen / kiosk type app, so none of the usual Apple user interface guidelines apply.