Moving and resizing windows broken on Safari 15

Describe the bug

Changes have been made to Safari 15 that prevent BTT's window moving/resizing via modifier keys feature from working properly. Specifically, the window moving/resizing works only when the mouse is hovering over Safari window chrome, not the content area. This is unlike the behavior with Safari 14 and earlier versions, where moving/resizing via modifier key(s) worked while hovering over any part of a Safari window.

It's worth mentioning that I am seeing this behavior using Safari Technology Preview (Release 127, Safari 15.0, WebKit 16612. running on macOS 11.4. It's possible that this issue does not exist with the macOS 12 (beta), but I don't have that OS available for testing.

Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):


Device information:

  • Type of Mac: MacBook Air 2020 (M1)
  • macOS version: 11.3
  • BetterTouchTool version: 3.562