gistfile1.txt

NSClipView

var drawsBackground: Bool
OBJECTIVE-C
@property BOOL drawsBackground
Discussion

If your NSClipView is enclosed in an NSScrollView, 
you should set the drawsBackground property on the NSScrollView. 
NSClipViewがNSScrollViewに埋め込まれている場合、NSScrollViewのdrawsBackgroundプロパティをセットするべきである。

Setting this property to NO on an NSScrollView has the added effect
of setting the NSClipView property copiesOnScroll to NO.
このプロパティをNOにセットすると、NSClipViewのcopiesOnScrollプロパティがNOに設定される効果があります。

The side effect of setting the drawsBackground property on the NSClipView is the appearance 
of “trails” (vestiges of previous drawing) in the document view as it is scrolled.
NSClipViewのdrawsBackgroundプロパティをセットすることの副作用はスクロールされたときのdocument view
内の後が見えることです。


e think copiesOnScroll behavior of NSClipView has changed in OSX 10.10?. 
Because while scrolling it is not asking for redraw of newly exposed area!!! 
Instead is asking for entire visible area to be redrawn every time. My 
application is not compatible with responsive scrolling, so I cannot use it and 
have turned it off. But I still need to keep that copiesOnScroll behavior. Any 
help is appreciated....