Switching between custom views using Toolbar - objective-c

Question

I have a single MainMenu.xib file and I have a window by the name "Preferences"
Also I have four different Custom Views with different Heights. and a Toolbar on that window.
I have linked every toolbar item to the -(void) switchViews:(id)sender; function. The views are linked and are showing up and are also changing but the problem is that if I change from one view to another and then back or to another, the content i.e. buttons, labels, checkboxes on the views keep moving upwards, the window still keeps on changing to right heights, but if I switch enough times the content would disappear from the view.. Any kind of help would be useful.
http://imgur.com/bV3NHa0,zgJCacA
http://imgur.com/bV3NHa0,zgJCacA#1
// FOR CHANGING VIEWS IN THE PREFERENCES WINDOW
- (IBAction)switchView:(id)sender {
long int tag = [sender tag];
NSView *view = [self viewForTag:tag];
NSView *previousView = [self viewForTag:currentViewTag];
currentViewTag = tag;
NSRect newFrame = [self newFrameForNewContentView:view];
[NSAnimationContext beginGrouping];
if ([[NSApp currentEvent] modifierFlags] & NSShiftKeyMask) {
[[NSAnimationContext currentContext] setDuration:1.0];
}
[[[[self preferences] contentView] animator] replaceSubview:previousView with:view];
[[[self preferences] animator] setFrame:newFrame display:YES];
[NSAnimationContext endGrouping];
}
- (NSView *)viewForTag:(long int)tag {
NSView *view = nil;
switch (tag) {
case 0:
view = generalView;
break;
case 1:
view = timesView;
break;
case 2:
view = menubarView;
break;
case 3: default: view = aboutView;
break;
}
return view;
}
- (NSRect)newFrameForNewContentView:(NSView *)view {
NSWindow *window = [self preferences];
NSRect newFrameRect = [window frameRectForContentRect:[view frame]];
NSRect oldFrameRect = [window frame];
NSSize newSize = newFrameRect.size;
NSSize oldSize = oldFrameRect.size;
NSRect frame = [window frame];
frame.size = newSize;
frame.origin.y -= (newSize.height - oldSize.height);
return frame;
}

Answer 1

with the problem you're describing and glancing at your code i would start to suspect this line...
frame.origin.y -= (newSize.height - oldSize.height);