VB 5.1.x does not release GUI focus for Gnome desktop -> GNOME problem

[James Moe]

VirtualBox v5.1.0 and .2 opensuse 42.1 gnome desktop 3.16.2

The Gnome desktop has a feature where moving the cursor to the upper left corner changes the window to display the open apps in the current window, and shows other desktops on the right side.

After upgrading to VB 5.1 from VB 5.0.24, when the guest has the focus, the above does not happen. If I click on the desktop taking the focus away from the guest, doing the above works as expected.

It does not matter what OS the guest is running; this occurs for os/2, windows XP, and windows 10.

[James Moe]

<sigh> This report can be closed. I apologize for the inconvenience.

I had neglected to update the guest additions. After doing so, the focus problem went away.

[James Moe]

Bxzzt! Wrong again.

The problem persists in a slightly different form. When guest has *captured* the mouse, the Gnome feature does not work.

[Michael Thayer]

You have me slightly confused there. It the guest has captured the mouse, how do you get the pointer to the upper left corner of the host screen? Full-screen guest? Or did you mean captured the keyboard?

[James Moe]

I have Guest Additions installed which allows the automatic transfer of the mouse from the host to the guest. If I have actually clicked within the guest, the Gnome feature does not work. If I click on the title bar of the guest window, for instance, (or completely outside the guest window) the feature works.

That is what I meant by "captured:" having clicked within the guest window.

Just to be sure, I just tried it to verify I had the description correct. Argh! There is no problem with the feature regardless of where I last clicked the mouse. So this has gone from being quite predictable to random to not-an-issue.

[Michael Thayer]

I assume that the problem here is guest keyboard capture. We handled this differently (in a way which did not work with Qt5) in 5.0 and earlier. Now what we do is to grab the keyboard (when auto-capture is enabled) when the machine window has the input focus and to drop the capture as soon as the user clicks outside of the window or removes the focus. I am guessing that the upper-left-corner feature does not work if someone else has the keyboard captured. You can see the keyboard status from the black or green indicator in the bottom right corner of the window.

[James Moe]

Ding! Yes, that is what is happening. When the keyboard is captured, the left-corner feature is disabled.

[Michael Thayer]

I'm afraid that after some thought I will not try to do anything about this. If you want to use this feature you will need to first release the keyboard capture, or disable automatic capturing. I consider it to be a bug in GNOME that this, dragging windows and opening menus do not work when any client has grabbed the keyboard, which is a standard X11 feature. Since I do not think that GNOME will fix these problems (KDE never had them, and Unity fixed the problem with window dragging in Ubuntu 16.04) I added complicated work-around code which will probably cause problems at some time for the other two in VirtualBox 5.1. However I would rather not do this for the hot-corner too.

Please, please, feel free to open a bug against GNOME Shell. I don't have the time to follow through on such a bug report just now, though I would be happy to comment on it or to be available to the developers for questions.

[Michael Thayer]

Out of interest, is this still a problem with Fedora 25? I would not expect this to affect GNOME under Wayland. That said, I rather dread finding out how our keyboard and mouse capture work generally with Wayland.

[stevewalsh]

The same problem as OP describes still exists on Fedora 25 with Wayland.

Can we blame GNOME if problem only started with VirtualBox 5.1.x and didn't exist with VirtualBox 5.0.x ?

[Michael Thayer]

I took a look at Fedora 25 and it is still doing a lot of X11 mixed in with Wayland, so that is probably the explanation. To clarify, we were using a different method to capture the keyboard in VirtualBox 5.0 which is not compatible with Qt5 (to which we switched in the 5.1 series) and overall had more problems that this one. We worked around other GNOME bugs but this one was too much work for too little benefit. Qemu and the GNOME RDP client work around it by releasing the keyboard capture (edited) when the mouse pointer leaves their window. We did not like that approach, as we considered it too confusing.