Bug 398340

Summary:	VirtualBOX, VMware Player - hot corners don't work, hot edges work as intended
Product:	[Plasma] kwin	Reporter:	Tomasz Feliksiak <vonom>
Component:	compositing	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal
Priority:	NOR
Version First Reported In:	5.12.6
Target Milestone:	---
Platform:	Kubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Tomasz Feliksiak 2018-09-06 22:47:41 UTC

In work I use Kubuntu 18.04.1 LTS as my main system and there everything works fine. I use top left corner for windows presentation and bottom right for desktop grid.

In home I have Windows 10 and VMware Player 14 (14.1.3 build-9474260) with exact the same Kubuntu 18.04.1 LTS. Earlier I used VirtualBOX (5.2.18 r124319 (Qt5.6.2)).

No mater on which VM software I run Kubuntu, hot corners doesn't work.

Inspired by bugs https://bugs.kde.org/show_bug.cgi?id=290887 and https://bugs.kde.org/show_bug.cgi?id=321259 I started testing this a bit, and noticed that hot edges are working normally.

Reproducible: Always

Steps to Reproduce:
1. Install Kubuntu 18.04.1 on VMware Player (with open-vm-tools) or VirtualBox (with vboxguestadditions) and go fullscreen (in window it's the same but harder to hit corner/edge of screen)
2. Bind any effect to the corners and edges
3. Throw your mouse in the corners and edges

Actual Results:
Hot corners doesn't work, hot edges are working

Expected Results:
Working hot corners and edges

Comment 1 Martin Flöser 2018-09-07 13:54:17 UTC

Please try to grab the mouse in the virtual machine. The seamless mouse integration might destroy the feature.

Comment 2 Tomasz Feliksiak 2018-09-07 23:17:35 UTC

(In reply to Martin Flöser from comment #1)
> Please try to grab the mouse in the virtual machine. The seamless mouse
> integration might destroy the feature.

You're absolutely right.
In VirtualBOX turning OFF mouse integration fixes hot corners (it's even possible to add shortcut to this operation). I didn't find that option in VMware Player (free version).

In both VirtualBOX and VMware Player after connecting USB mouse to virtual machine (and in the same time disconnecting from host) fixes hot corners too. I didn't spend much time on this but getting back mouse to host for me was possible only after shutting off guest. Maybe there is some other way.

Nonetheless is that the right way to go? Shouldn't hot corners work like hot edges do? If someone switch from host to guest as often as me, switching mouse from guest to host is so much problem it's absolutely pointless to use hot corners (of course I can live without them but that's not the way to fix bugs).

Of course I'm interested how hot corners differ from hot edges in this situation and I will be gratefull for explanation. For now I still consider this as a bug.

Comment 3 Martin Flöser 2018-09-08 19:18:18 UTC

There's probably not much we can do about it - starting from the point that we don't know we are virtualized.

Edges and corner work the same way: the mouse cursor is pushed back a pixel and on active push against the edge or corner the action is triggered. Why this doesn't work virtualized is hard to guess. A theory could be the top pixel being stolen by the vm's header bar. Thus a switch from VM to host and thus destroying our logic.