I have a second monitor attached to my laptop. Both have the same screen resolution. The external (second) monitor is placed to the left of the internal (first) monitor (portrait mode). When I move the mouse cursor to the left edge of the first monitor (landscape mode), it suddenly appears on the second monitor following the gestures of the first one. This also happens on the second screen, if the mouse cursor is close to the first screen. It seems there is an overlapping area between both screens, although the screens are not overlapping in gnome system configuration for displays. This only happens with the mouse cursor, not with application windows.

Fedora 27, kernel-4.14.6-300.fc27.x86_64.

VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
	Subsystem: Lenovo Device 21f5
	Kernel driver in use: i915



Steps to Reproduce:
1. Connect an external monitor over VGA.
2. Extend and place the screen to the left (or right) of the internal screen.
3. Move mouse cursor towards the second screen.