Open Radar

 
Summary:

When using left/right keys to change selection in an IKImageBrowserView, and that selection change causes a scroll, the scroller will flash white before showing. It's a very quick flash, but with an app in with a darker UI it can be quite jarring.

Steps to Reproduce:

- Setup a single row IKImageBrowserView with a darker background
- Use keyboard keys to navigate to edge
- Wait until NSScroller disappears (assuming overlay scrollers)
- Hit right arrow key

Expected Results:

- Selection  Change
- Scroll to right
- Scrollers fade in, then out.

Actual Results:

- Selection Change
- Scroll to right
- Scroller flashes white
- Scroller then draws on top
- Scroller fades out

Regression:

Unknown.

Notes:

I've attached a sample project that should reproduce it. It contains nothing fancy, no NSScrollView/NSScroller/IKImageBrowserView subclassing. http://d.pr/f/PvYv 

I'll also attach a video clearly showing a white flash over the scroller. : http://d.pr/v/VV2M