FB9024440: NSProgressIndicator looses the animation state when switching to indeterminate mode.

[macmade]

• Date: 2021-03-01
• Resolution: Open
• Area: AppKit
• OS: macOS
• Type: Incorrect/Unexpected Behavior
• Keywords: appkit, progress, indicator

Description

When using NSProgressIndicator in progress bar mode, the animation state is reset when switching to indeterminate mode.
As a result, the progress bar no longer animates.

Please see the example project for a demonstration of this behavior, which is new in macOS 11.

The demo app starts with an animating and indeterminate progress bar:

1 - Uncheck the "Indeterminate" checkbox.
2 - Move the slider to some position to increase the progress bar value.
3 - Check the "Indeterminate" checkbox.

The progress bar is not animated, although the "animate" binding is still on.
Toggling "animate" fixes the animation status, but this whole behavior is incorrect.
Previous macOS versions did not behave this way.

Files

Progress.zip