Changing appearance of UIBarButtonItem also changes position of navigationbar and toolbar?

Question

once again I have a problem with my custom navigation- and toolbar: I've customised their tintColor and the font by using the appearance proxy in didFinishLaunchingWithOptions . Initially the bars should be hidden by setting their center outside the visible area in viewDidLoad . By single-tapping I use my own animation to slide the bars in/out.
Everything was working just fine until the next step:
I wanted the UIBarButtonItems to have the same font like i used in the bars, so I went back to didFinishLaunchingWithOptions and added the following code:

[[UIBarButtonItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
[UIFont fontWithName:FONT_HEADER size:0.0],UITextAttributeFont,nil] forState:UIControlStateNormal];

It works just fine for the font part, but somehow it also sets the bars back into the visible position before viewWillAppear so the bars are not initially hidden anymore. I tried to find out what causes this unmeant repositioning and couldn't find any connection. I also tried to reset the position at some later point like viewWillAppear but this somehow doesn't work for the toolbar.

EDIT: The described behaviour does only occur on devices with iOS 5 though. On the iOS6 simulator everything still seems fine.

Does anyone have a hint for me what is going wrong here or how I could smoothly solve this problem? Thanks in advance

Answer 1

   [[UIBarButtonItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
[UIFont fontWithName:FONT_HEADER size:0.0],UITextAttributeFont,nil] forState:UIControlStateNormal];

what's the FONT_HEADER here? Did you check if the ios 5 support this font?