NSProgressIndicator can't set background color to white

Question

When I set my progress indicator's background to green, it works as expected.

Code:

loadingIndicator.wantsLayer = true
loadingIndicator.layer?.backgroundColor = NSColor.greenColor().CGColor

Result:

But when I set the background color to white, the background color stays gray (instead of changing to white).

Code:

loadingIndicator.wantsLayer = true
loadingIndicator.layer?.backgroundColor = NSColor.whiteColor().CGColor

Result:

Why does setting the background color to white not work, but green does? How can I correct this issue? I'm on OS X 10.11.4.

EDIT: This apparently only happens when the progress indicator is inside a view that was presented as a popover.

Answer 1

I had same issue when I use NSProgressIndicator inside NSPopover.

My solution was to set appearance to popover like below.

popover.appearance = NSAppearance(named: NSAppearanceNameAqua)

• Tried on OSX 10.11.5 / Xcode7.3.1
• Any other name except for NSAppearanceNameVibrantDark also worked

I'm not sure why this happens, but after setting the property I got correct white background color.

Screenshot: white background progress inside popover

Answer 2

I've found a way to fix this. The CALayer of the NSProgressIndicator has a sublayer that is showing the tinted background color you are seeing. Hiding that sublayer will cause no background to ever be shown, and keep the spinner visible.

CALayer *layer = [[self popoverProgressIndicator] layer];
CALayer *backgroundLayer = [[layer sublayers] firstObject];
[backgroundLayer setHidden:YES];

I've only seen this issue when inside of an NSPopover where I was using the solution here to change the background.