Construct and manage a graphical, event-driven user interface for your macOS app using AppKit.

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Crash when assigning NSImage to `@objc dynamic var` property
Xcode downloaded a crash report for my app which I don't quite understand. It seems the following line caused the crash: myEntity.image = newImage where myEntity is of type MyEntity: class MyEntity: NSObject, Identifiable { @objc dynamic var image: NSImage! ... } The code is called on the main thread. According to the crash report, thread 0 makes that assignment, and at the same time thread 16 is calling [NSImageView asynchronousPreparation:prepareResultUsingParameters:]. What could cause such a crash? Could I be doing something wrong or is this a bug in macOS? crash.crash
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174
Aug ’25
NSTextView.shouldDrawInsertionPoint doesn't work with TextKit 2
The following code only ever causes shouldDrawInsertionPoint to be printed (no drawInsertionPoint), but even if that method returns false, the blinking insertion point is still drawn. On the other hand, with TextKit 1 it works as expected. Is there a way to hide the default insertion point in TextKit 2? My app draws its own. I've filed FB13684251. class TextView: NSTextView { override var shouldDrawInsertionPoint: Bool { print("shouldDrawInsertionPoint") return false } override func drawInsertionPoint(in rect: NSRect, color: NSColor, turnedOn flag: Bool) { print("drawInsertionPoint", flag) } } ``
Topic: UI Frameworks SubTopic: AppKit Tags:
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140
Aug ’25
vImageConverter_CreateWithCGImageFormat Fails with kvImageInvalidImageFormat When Trying to Convert CMYK to RGB
So I get JPEG data in my app. Previously I was using the higher level NSBitmapImageRep API and just feeding the JPEG data to it. But now I've noticed on Sonoma If I get a JPEG in the CMYK color space the NSBitmapImageRep renders mostly black and is corrupted. So I'm trying to drop down to the lower level APIs. Specifically I grab a CGImageRef and and trying to use the Accelerate API to convert it to another format (to hopefully workaround the issue... CGImageRef sourceCGImage = `CGImageCreateWithJPEGDataProvider(jpegDataProvider,` NULL, shouldInterpolate, kCGRenderingIntentDefault); Now I use vImageConverter_CreateWithCGImageFormat... with the following values for source and destination formats: Source format: (derived from sourceCGImage) bitsPerComponent = 8 bitsPerPixel = 32 colorSpace = (kCGColorSpaceICCBased; kCGColorSpaceModelCMYK; Generic CMYK Profile) bitmapInfo = kCGBitmapByteOrderDefault version = 0 decode = 0x000060000147f780 renderingIntent = kCGRenderingIntentDefault Destination format: bitsPerComponent = 8 bitsPerPixel = 24 colorSpace = (DeviceRBG) bitmapInfo = 8197 version = 0 decode = 0x0000000000000000 renderingIntent = kCGRenderingIntentDefault But vImageConverter_CreateWithCGImageFormat fails with kvImageInvalidImageFormat. Now if I change the destination format to use 32 bitsPerpixel and use alpha in the bitmap info the vImageConverter_CreateWithCGImageFormat does not return an error but I get a black image just like NSBitmapImageRep
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1.3k
Aug ’25
macOS 26: NSTokenField crashes due to NSGenericException caused by too many Update Constraints
This example application crashes when entering any text to the token field with FAULT: NSGenericException: The window has been marked as needing another Update Constraints in Window pass, but it has already had more Update Constraints in Window passes than there are views in the window. The app uses controlTextDidChange to update a live preview where it accesses the objectValue of the token field. If one character is entered, it also looks like the NSTokenFieldDelegate methods tokenField(_:styleForRepresentedObject:) tokenField(_:editingStringForRepresentedObject:) tokenField(_:representedObjectForEditing:) are called more than 10000 times until the example app crashes on macOS Tahoe 26 beta 6. I've reported this issue with beta 1 as FB18088608, but haven't heard back so far. I have multiple occurrences of this issue in my app, which is working fine on previous versions of macOS. I haven't found a workaround yet, and I’m getting anxious of this issue persisting into the official release.
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Aug ’25
Sleep State Notification Inconsistencies on MacBook Devices When Unplugged
There are inconsistent behaviors in sleep/wake notification callbacks across different MacBook devices and macOS versions when the device is not connected to power, with or without external displays, entering sleep mode by closing the lid, and waking up from sleep by opening the lid. When monitoring the following Objective-C notifications: NSWorkspaceScreensDidSleepNotification NSWorkspaceScreensDidWakeNotification NSWorkspaceWillSleepNotification NSWorkspaceDidWakeNotification Different devices exhibit varying notification trigger patterns: Some devices trigger all four notifications properly Some devices fail to trigger NSWorkspaceScreensDidWakeNotification Some devices fail to trigger NSWorkspaceDidWakeNotification Some devices fail to trigger NSWorkspaceWillSleepNotification These inconsistencies make it challenging to implement reliable sleep/wake detection logic across different MacBook models and macOS versions.
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74
Aug ’25
NSToolbar doesn't restore displayMode when NSWindow.titleVisibility = .hidden
Apparently when setting a window to hide its title, the toolbar's displayMode is not restored when relaunching the app. For example, by default my app sets to show toolbar icons only, but when right-clicking it, selecting "Icon and Text" and relaunching the app, it's again "Icon Only". Is there a workaround? I've filed FB17144212. class ViewController: NSViewController, NSToolbarDelegate { override func viewDidAppear() { let toolbar = NSToolbar(identifier: "toolbar") toolbar.delegate = self toolbar.autosavesConfiguration = true toolbar.displayMode = .iconOnly view.window?.titleVisibility = .hidden view.window?.toolbar = toolbar view.window?.toolbarStyle = .unified } func toolbarAllowedItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] { return [.init(rawValue: "item")] } func toolbarDefaultItemIdentifiers(_ toolbar: NSToolbar) -> [NSToolbarItem.Identifier] { return [.init(rawValue: "item")] } func toolbar(_ toolbar: NSToolbar, itemForItemIdentifier itemIdentifier: NSToolbarItem.Identifier, willBeInsertedIntoToolbar flag: Bool) -> NSToolbarItem? { let item = NSToolbarItem(itemIdentifier: itemIdentifier) item.image = NSImage(named: NSImage.addTemplateName)! item.label = "item" return item } }
Topic: UI Frameworks SubTopic: AppKit Tags:
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68
Aug ’25
How to speed-up initial UI rendering faster in AppKit?
I am developing an AppKit application in MacOS with Swift. Our application requires a complex, multi-windowed interface and must deliver a very fast, responsive experience. As a performance test, I built a sample app that creates 3 windows programmatically, each containing 500 NSTextFields (with each text-field assigned 35 different properties). Code flow: https://gist.github.com/Raunit-TW/5ac58ac9c6584f93e2ee201aa8118139 This takes around 77 milliseconds to render the windows - I need to find a way to reduce this time, as low as possible. Thanks.
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142
Aug ’25
[TextKit2] - Wrong document height sometimes ?
Hello 👋 I'm playing with the Apple TextKit2 sample app (particularly on macOS). I found that on some long document the evaluated height given by enumerateTextLayoutFragments API is wrong (or at least not I expect) which imply I can no longer scroll in my document even if I have not reached the end of it (which is not what I expect as you can guess). I'm clearly missing a point here. I can reproduce it on the Apple sample app by only changing the text content: https://developer.apple.com/documentation/UIKit/using-textkit-2-to-interact-with-text Using TextKit2, is it my responsability as developer to check that I've reached end of the scrollview whether not being at the end location of the document and call some specific TextKit2 API to invalidate estimation or something ? Here is an updated version of the Apple sample app with another text content that show the issue. https://drive.google.com/file/d/1jtTD84oqGAG4_A9DfqFl_yHmbLKhF1e8/view?usp=sharing Environment: Xcode 16.4 - macOS 15.6 If someone could help me with this, I would be extremely grateful. It puzzles me. NB: I've observed that resizing the window a bit seems to force a new layout and make TextKit2 returns a more accurate height, ... until you reach the end of the document.
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106
Aug ’25
Xcode 26 XIB ignores difference between NSView frame and alignment rectangles
In the last three betas of Xcode 26, opening XIB files that rely on the older struts-and-springs setup (rather than Auto Layout) has exposed a new problem: Xcode 26 ignore the difference between a view’s frame and alignment rectangle. If you had arranged views using their frame rectangle (the default for the old method) this causes two problems: All UI widgets are both larger and no longer aligned. Switching between frame and alignment rectangles while configuring any NSView (through the inspector setting) has no effect. Is anyone else seeing this? It’s one thing to convert a few smaller views to Auto-layout (its reliance on alignment rectangles makes it immune to the "death" of frame rectangle-based layout) it is a rather different task to re-layout thousands of UI widgets as a result of this one bug. Filed as FB18835363
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166
Jul ’25
Structured concurrency + preconcurrency API (SFAuthorizationPluginView)
I'm having trouble dealing with concurrency with the SFAuthorizationPluginView. Does anybody know how this can be solved? https://developer.apple.com/documentation/securityinterface/sfauthorizationpluginview The crux of it is: If I inherit an object as part of an API, and the API is preconcurrency, and thus is nonisolated (but in reality is @MainActor), how do I return a @MainActor GUI element? https://developer.apple.com/documentation/securityinterface/sfauthorizationpluginview/firstresponder() The longer story: I made my view class inherit SFAuthorizationPluginView. The API is preconcurrency (but not marked as preconcurrency) I started using concurrency in my plugin to retrieve data over XPC. (https://developer.apple.com/documentation/xpc/xpcsession + https://developer.apple.com/documentation/swift/withcheckedthrowingcontinuation(isolation:function:_:)) Once I retrieve the data over XPC, I need to post it on GUI, hence I've set my view class as @MainActor in order to do the thread switch. Swift compiler keeps complaining: override func firstResponder() -> NSResponder? { return usernameField } "Main actor-isolated property 'usernameField' can not be referenced from a nonisolated context; this is an error in the Swift 6 language mode" override func firstResponder() -> NSResponder? { MainActor.assumeIsolated { return usernameField } } "Sending 'self' risks causing data races; this is an error in the Swift 6 language mode" I think fundamentally, the API is forcing me to give away a @MainActor variable through a nonisolated function, and there is no way to shut up the compiler. I've tried @preconcurrency and it has no effect as far as I can tell. I've also tried marking the function explicitly as nonisolated. The rest of the API are less problematic, but returning a GUI variable is exceptionally difficult.
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668
Jul ’25
No MDM settings to control macOS pasteboard privacy?
For context, my company develops a data loss prevention (DLP) product. Part of our functionality is the ability to detect sensitive data being pasted into a web browser or cloud-based app. The AppKit release notes for April 2025 document an upcoming “macOS pasteboard privacy” feature, which will presumably ship in macOS 26. Using the user default setting “EnablePasteboardPrivacyDeveloperPreview” documented in the release notes, I tested our agent under macOS 15.5, and encountered a modal alert reading " is trying to access the pasteboard" almost immediately, when the program reads the General pasteboard to scan its contents. Since our product is aimed at enterprise customers (and not individual Mac users), I believed Apple would implement a privacy control setting for this new feature. This would allow our customers to push a configuration profile via MDM, with the “Paste from Other Apps” setting for our application preset to “Allow”, so that they can install our product on their endpoints without manual intervention. Unfortunately, as of macOS 26 beta 4 (25A5316i), there does not seem to be any such setting documented under Device Management — for example in PrivacyPreferencesPolicyControl.Services, which lists a number of similar settings. Without such a setting available, a valuable function of our product will be effectively crippled when macOS 26 is released. Is there such a setting (that I've overlooked)? If not, allow me to urge Apple to find the resources to implement one, so that our customers can preset “Paste from Other Apps” to “Allow” for our application.
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653
Jul ’25
SwiftUI APIs for macOS app
What are the SwiftUI equivalent of NSSplitViewController.automaticallyAdjustsSafeAreaInsets NSToolbarItem.style These were introduced in the WWDC 2025 session named "Build an AppKit app with the new design". Jeff introduced only the AppKit API's while there was no mention of SwiftUI API
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231
Jul ’25
Set edge effect style in AppKit
In macOS 26 beta 2 it is possible to set an edge effect style via UIKit using the .scrollEdgeEffectStyle property. (note: I haven't tested this, I'm just looking at the documentation). See: https://developer.apple.com/documentation/swiftui/view/scrolledgeeffectstyle(_:for:) Is there an equivalent API for AppKit-based apps? I can't seem to find any additions in NSView or NSScrollView or elsewhere that seem relevant. Scroll edge effects are mentioned in the "Build an AppKit app with the new design" talk here, which heavily implies it must be possible from AppKit: https://developer.apple.com/videos/play/wwdc2025/310/?time=567
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266
Jul ’25
Where is the NSToolbarItem badge property in macOS Tahoe?
According the video "Build an AppKit app with the new design" (https://developer.apple.com/videos/play/wwdc2025/310/), it is now possible to add a badge on a NSToolbarItem object. However, in don't see a badge in the NSToolbar API. The code example in the video includes for example "NSItemBadge.count(4)", but the only Google result for this is the video mentioned above. Is this still work in progress or I'm overlooking something?
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101
Jul ’25
Debug an issue with NSWindow becoming narrow
For months now we're trying to find an issue with one of our apps, were a window suddenly becomes narrow and can't be resized horizontally any more. It's a bug that only happens sporadically and we can't provide a "focused test project" to demonstrate the issue; thus we can't ask for code-level support at this moment. To debug this issue, we've overwritten a private method on NSWindow that gets the constrained window min and max sizes (valuable hint of Kristin from the AppKit team in a WWDC 2025 one-on-one session where I was able to show it to her in my debugger). When the bug hits, the maxSize's width (usually 10000) becomes smaller than the minSize's width. One way (but not the only one) to trigger this issue is to move the window from one display to another and back. Sometimes the bug triggers after a few back-and-forth movements, sometimes it takes minutes to trigger or I give up… but for other people the bug happens seemingly out of nowhere (of course there must be a trigger but we haven't noticed common patterns yet). It looks like an AutoLayout issue since a suspicious thing happens when the bug triggers: calling constraintsAffectingLayoutForOrientation:NSLayoutConstraintOrientationHorizontal on the NSThemeFrame usually returns just two constraints. But when the bug triggers, it returns a whole bunch of constraints, related to all kind of views of our app. Asking the NSThemeFrame for its direct constraints still shows the same two constraints are present and active (NSWindow-current-width and NSWindow-x-anchor). How to proceed in hunting down this issue when we're unable to produce a demo project? We can only reproduce the bug with our big product, and only sporadically: sometimes I can trigger it in a minute, sometimes it takes me 15 minutes or even more. Issue happens on macOS 15 (currently running 15.5).
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112
Jul ’25
Force NSDocument save panel to select most specific type in format popup button
My app supports different plain text file formats, including the standard .txt and Markdown. When creating a new document, my app already asks which format it should have, so when saving it, I would expect that the save panel already selects that format in the popup button, but currently it always selects "Plain Text". For example, I would expect for a Markdown document that it selects "Markdown" instead of "Plain Text". Is there a way to force it to select the most specific format matching the document format?
Topic: UI Frameworks SubTopic: AppKit Tags:
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101
Jul ’25
How to set accessibility-label to NSTextAttachment ?
I have the following method to insert @mentions to a text field: func insertMention(user: Token, at range: NSRange) -> Void { let tokenImage: UIImage = renderMentionToken(text: "@\(user.username)") let attachment: NSTextAttachment = NSTextAttachment() attachment.image = tokenImage attachment.bounds = CGRect(x: 0, y: -3, width: tokenImage.size.width, height: tokenImage.size.height) attachment.accessibilityLabel = user.username attachment.accessibilityHint = "Mention of \(user.username)" let attachmentString: NSMutableAttributedString = NSMutableAttributedString(attributedString: NSAttributedString(attachment: attachment)) attachmentString.addAttribute(.TokenID, value: user.id, range: NSRange(location: 0, length: 1)) attachmentString.addAttribute(.Tokenname, value: user.username, range: NSRange(location: 0, length: 1)) let mutableText: NSMutableAttributedString = NSMutableAttributedString(attributedString: textView.attributedText) mutableText.replaceCharacters(in: range, with: attachmentString) mutableText.append(NSAttributedString(string: " ")) textView.attributedText = mutableText textView.selectedRange = NSRange(location: range.location + 2, length: 0) mentionRange = nil tableView.isHidden = true } When I use XCode's accessibility inspector to inspect the text input, the inserted token is not read by the inspector - instead a whitespace is shown for the token. I want to set the accessibility-label to the string content of the NSTextAttachment. How?
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835
Jul ’25
Crash in IndexSet.map during menu item validation in client report downloaded by Xcode
For many years I've had the following code to access the active objects of a table view in my App Store app: class MyViewController: NSViewController: NSMenuItemValidation { private var tableView: NSTableView! private var objects = [MyObject]() func numberOfRows(in tableView: NSTableView) -> Int { return objects.count } func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? { // make view for row } private var activeObjects: [MyObject] { return tableView?.activeRowIndexes.map({ objects[$0] }) ?? [] } func validateMenuItem(_ menuItem: NSMenuItem) -> Bool { let activeObjects = self.activeObjects ... } } extension NSTableView { var activeRowIndexes: IndexSet { return clickedRow == -1 || selectedRowIndexes.contains(clickedRow) ? selectedRowIndexes : IndexSet(integer: clickedRow) } } In one of the recent updates, I wanted to add some kind of header to the table view, so I decided to add a row at the beginning and offset the indexes by 1. func numberOfRows(in tableView: NSTableView) -> Int { return objects.count + 1 } func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? { if row == 0 { // make header view } else { // make view for row - 1 } } private var activeObjects: [MyObject] { return tableView?.activeRowIndexes.subtracting(IndexSet(integer: 0)).map({ objects[$0 - 1] }) ?? [] } But since I added this change, Xcode regularly downloads crash reports from clients crashing during menu item validation in IndexSet.map with reason Code 5 Trace/BPT trap: 5. I assumed that I was accessing an invalid array index, so I added some debug code: the crash report would then show the invalid index beside the crashed thread's name. private var activeObjects: [MyObject] { return tableView?.activeRowIndexes.subtracting(IndexSet(integer: 0)).map({ i in if !objects.indices.contains(i - 1) { Thread.current.name = (Thread.current.name ?? "") + ". Invalid index \(i - 1) for count \(objects.count)" preconditionFailure() } return objects[i - 1] }) ?? [] } But the crash reports for this new app version look just like the old ones and the thread name is not changed. Indeed, when recreating an invalid index access on my Mac, the crash report mentions Array._checkSubscript(_:wasNativeTypeChecked:), which does not appear in the crash reports downloaded by Xcode. Manually symbolicating the crash report also doesn't give any more information: all lines referring to my app code are resolved to either /<compiler-generated>:0 or MyViewController.swift:0. Apparently the problem is not an invalid array index, but something else. Does anybody have a clue what the problem could be? (Note: the crash report mentions Sequence.compactMap because now I'm effectively calling tableView?.activeRowIndexes.compactMap, but the same crash happened before when calling IndexSet.map, which would appear in the crash report as Collection.map.) crash2.crash
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89
Jul ’25
The menu can't be shown in background process in MacOS 26(beta)
After I upgraded to MacOS 26(beta), my program caused the system to pop up a window as shown in the following picture. My application is a process with only a tray icon. I found that my tray icon is not displayed in the current version, even though I clicked the "Always Allow" button. Here are my questions: 1.Will this related feature remain consistent in the official release? 2.How can I create a cmd process that only displays a system tray icon (no main window) like Alfred?
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Jul ’25