I’m seeing in issue on iOS 27 with TextKit 1 backed UITextViews where grammar checking makes part of the text disappear. For TextKit 2 views, there's a blue underline and a shimmer effect that's applied to the text when a grammatical error is detected. For TextKit 1 views the underline appears but instead of the shimmer effect, the text just disappears. Steps to reproduce: Create a UITextView using TextKit 1: UITextView(usingTextLayoutManager: false) Fill it with a very long document (makes the bug easier to reproduce). Type a phrase that triggers a grammar correction, such as “self aware”. Wait for the system to suggest “self-aware”. The blue underline appears but the two words disappear. I've found a partial workaround by overriding NSLayoutManager.drawGlyphsForGlyphRange and calling CGContextSetFillColorWithColor on the affected range, but this isn't great. Filed as FB24319258. Has anyone else encountered this on the iOS 27 betas? Would appreciate any guidance.

Hi, I wanted to know what is the best way to detect whether a part of string has an unavailable character, '□' (tofu box or last resort character). So far it seems to be that we will have to parse all the strings and individually check for each character and whether or not it is a part of the Unicode Scalar. And since we are a business application that deals with a lot of data as strings, this will be rather performance heavy. So wanted to know if there were any other better or more efficient ways to go about this?

When using the writingToolsBehavior API on a TextField and the app compiled with the iOS 26 SDK is run on an iOS 18 device, the app crashes with a symbol not found error. It only crashes on the release build configuration and not on debug. dyld[5274]: Symbol not found: _$s7SwiftUI17EnvironmentValuesV21_writingToolsBehaviorAA07WritingfG0VSgvg Referenced from: <1306655E-6DF7-3B2A-94A3-7202149E82F3> /private/var/containers/Bundle/Application/88E47904-4884-4279-9E96-0EC366970389/WritingToolsTest.app/WritingToolsTest Expected in: <165D3305-401E-37C2-8387-C1BFB54CFFDE> /System/Library/Frameworks/SwiftUI.framework/SwiftUI Feedback ID: FB17980516