O fio Como desativar os cantos fixos no Windows 10? from answers.microsoft.com trata o mesmo problema:
When moving the mouse from the left monitor to to the top left of the right monitor the 6 pixel corner will catch your mouse.
I have similar problem in windows 8.1 and changing MouseCornerClipLength in registry to 0 from 6 and disable Corner Navigation in Taskbar and Start menu properties helped.
Anyway in Win10 i can't find MouseCornerClipLength, Corner Navigation disabled at all and adding same registry keys won't help.
A resposta em 4 de junho de 2015, por um engenheiro de suporte da Microsoft chamado Vijay B, foi:
We are aware of this issue and it is currently being investigated. Stay tuned and we will update this thread when additional information becomes available.
If any other posters experiencing this have not submitted this through the Windows Feedback App, please do so. This article http://answers.microsoft.com/en-us/insider/forum/insider_apps-insider_feedback/how-to-share-feedback-on-windows-10-technical/5e501781-a580-43e3-8926-40ae19343805 explains using the Windows Feedback App.
Parece que sua única opção é esperar por uma melhoria futura, ou para algum hacker descobrir o hack certo. Adicionar sua voz ao Windows Feedback App pode ajudar .
[ EDIT ] O aplicativo de código aberto Non Stick Mouse é dito para oferecer uma solução no caso de vários monitores. O desenvolvedor afirma:
What it does is hop the mouse over the sticking corners, as well as the screen edges when moving windows. Thus it allows the dragging of windows through screens without your mouse getting hijacked by the Snap Assist.
[...]
This application does not read or write to any drive, it does not access the registry or connect to the Internet.
Aviso: Foi observado nos comentários que O virustotal encontra malware na versão mais recente do "non stick mouse".