On Catalina GM, secondary display uses negative x-axis for Snap Areas

Describe the bug
On Catalina GM, the secondary display uses negative x-axis values for Snap Areas. This is not necessarily a bug but just a change in defining Snap Areas. My primary display is on the right, and my secondary display is on the left. For Snap Areas, my primary display is 0–2560x, and my secondary display is −2560–0x.

Prior to Catalina, Snap Area dimensions were independent for each display. It appears now that the entire desktop area is defined by the location of the primary display, with the main display representing 0x.

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


Device information:

  • Type of Mac: iMac17,1 and LED Cinema Display (secondary display)
  • macOS version: 10.15 (19A582a)
  • BetterTouchTool version: 3.204 (1380)

Additional information (e.g. StackTraces, related issues, screenshots, workarounds, etc.):

“Displays have separate spaces” is enabled, as it has been for me in previous macOS versions. This is a clean install of Catalina and of BTT.

Unless I misunderstand, this has always been like this when multiple screens are used.
Snap areas allow you to snap windows to other displays, which is why it is necessary to allow this. The zero origin on macOS is defined by the main display.

The position of the snap area itself is display specific though (only the area it snaps to needs to be in relation to the main origin)

Using my same setup, on High Sierra and Mojave, each display started at 0x. Anyway, it is not a bug and may just be a change in how Catalina defines the desktop.