Describe the bug
Over the last few days I've had two occasions where switching applications (eg by clicking on the window of any other application) causes a short but significant freeze of most of the system.
Specifically, during these freezes:
- the mouse pointer locks in place
- keyboard input is ignored
- Activity Monitor doesn't refresh
- a playing video will usually freeze, although the audio continues
The freezes last 5-10 seconds. After it's over, I can see tailspin coming up to the top of the CPU % chart in Activity Monitor. And I have a corresponding list of logs in /Library/Logs/DiagnosticReports - whatever app I try to switch to or from (not sure which) gets a *.spin log.
In total this has happened twice. The first time was four days ago, and it was a serious enough issue that I thought it might be hardware or OS related and I rebooted.
The second time, today, I isolated BTT as the cause - as soon as BTT was closed, the freezes stopped. After re-opening BTT the freezes have not re-occurred. BTT had been running for 96+ hours before the issue occurred for the second time (I never put my system to sleep), so if it's timing/leak related, it probably won't happen again for a while.
The issue only occurred when switching applications. Switching between windows of the same application (eg clicking between multiple different Firefox windows, each on a different monitor) did not trigger the issue. But it happened whenever a different app was selected in any way: clicking on its window, clicking on its menu bar icon, or closing one app such that another became focused.
Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):
- Type of Mac: MP 5.1
- macOS version: High Sierra 10.13.6 B3
- BetterTouchTool version: 2.525 Alpha
Additional information (e.g. StackTraces, related issues, screenshots, workarounds, etc.):
BTT and spindump logs available on request.