NSButton rendering issues when displayed over NSImageView

Question

I have a NSButton sibling on top of a NSImageView.

Whenever I click the window, there are some rendering issues. It looks like this:

enter image description here

As you can see, the white edges are the problem.
Strangely, this problem even persists if I override drawRect:.
Nothing gets rendered at all, but whenever I click it, those white edges appear.

Also, when the background-image changes, the button gets redrawn and the edges disappear.

Any idea what might cause this?

EDIT

I found out that this actually happens with every single instance of NSView
and it actually clears part of the buffer (you can see the desktop wallpaper):

enter image description here

EDIT 2

I also just found out that this does not happen if I layer-back the windows content-view.

check it, if it could solve ur problem http://www.cocoawithlove.com/2010/11/back-to-mac-12-features-from-ios-i-like.html — ChenSmile, Feb 14 '14 at 08:45
@Immi Hm.. Which one of them specifically? I looked at all of them, I didn't see which one you were referring to. — IluTov, Feb 14 '14 at 08:49
@Immi Like I said, disabling the entire `NSButtonCell` by overriding `drawRect:` still gives me the same behaviour. I wouldn't know what else can possibly cause this issue. — IluTov, Feb 14 '14 at 08:53
@Immi There is no code snippet, this happens even for a standard `NSButton`. — IluTov, Feb 14 '14 at 08:54
i have never faced such type of prob... i'll suggest u to look carefully at apple docs. — ChenSmile, Feb 14 '14 at 08:56
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/47486/discussion-between-immi-and-nsaddict) — ChenSmile, Feb 14 '14 at 08:57
Is the button a subview of the image view of just place above. I have had some strange things happen adding subviews to NSImageView so don't do that. — Daniel Farrell, Feb 14 '14 at 14:29

score 0 · Accepted Answer · answered Mar 03 '14 at 18:03

Well, this question was impossible for anyone to answer.

My window had a custom contentView, which was just drawing a view with rounded corners.
Instead of using self.bounds, I used dirtyRect to draw the background.

So when the contentView wanted to redraw the background of the controls that were updated, those rounded corners were cut out.

NSButton rendering issues when displayed over NSImageView

EDIT

EDIT 2

1 Answers1