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Sheet dismissal bug when window is hidden

Our customer found the following issue. In our apps we are showing some sheets for displaying progress to the user (downloading a bunch of images for example). I was not aware that if you ALT + CLICK in macOS ouside your window it gets hidden. When you do this and dismiss the sheet meanwhile an empty sheet remains on top of your window.

This bug is filed as rdar://30071930 and on Open Radar.

In the sample you can find on our Radar Samples GitHub Repo you can see the bug in action. This is how it should look:

and this is the empty sheet showing:


Sheet is not getting dismissed when window is hidden

Steps to Reproduce

  1. Run sample
  2. Click on Present Sheet button
  3. ALT + Click outside window to hide window
  4. Wait more than 5 seconds and click the app to show

Expected Results

  • Sheet should get dismissed

Actual Results

  • Empty sheet remains after dismissal


  • This happens on macOS 10.12 (Sierra)

The mentioned Sheet bug sample app is on our Radar Samples GitHub repo.

Categories: Bug Reports

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  1. Sheet dismissal bug when window is hidden – Techvibesnow

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