I have installed on a OS13.1 64 bit host in virtualbox a OS 13.1 64 bit guest. As I have 2 physical screens I have set the parameters in Virtual Box Manager to 2 screens. After the installation I installed the guest additions and everything seemed to run quite well.
In my 2. virtual machine I have Win7 64 bit running as a guest, also supporting 2 screens, each screen in its own window, without any problems.
MY PC has in total 16GB of ram; the Win7 guest can use 8 GB thereof and the OS13.1 guest 4GB. So 4gb are left for the host.
My AMD processor has 6 kernels, so I have given 3 for the WIN and 2 for the OS13.1 guest with an execution cap of 90% for both clients.
The Win client runs on desktop 1 and the OS client on desktop 2 of the host.
Whenever I switch from the OS client desktop to the win desktop, work some time there and then go back to the OS desktop, the 2. window of the OS13.1 guest is gone and to get it back, I have to restart the client completely. Just doing a restart does not work !
The runtime attributes of the session information of the OS13.1 guest before and after is equal:
**Runtime Attributes** Screen Resolution 1 1904x961x32 @1904,0 Screen Resolution 2 1904x961x32 @0,0 VM Uptime 0d 01:17:35 Clipboard Mode Bidirectional Drag and Drop Mode Bidirectional VT-x/AMD-V Active Nested Paging Active Unrestricted Execution Inactive Paravirtualization Interface KVM Guest Additions 5.0.4_SUSE r102546 Guest OS Type Linux 2.6 / 3.x / 4.x (64-bit) Remote Desktop Server Port Not Available
I also have always the problem that the system forgets which screen is #0 and which is #1. In System Settings/ Hardware/Display and Monitor/Display configuration I always find after starting the OS guest VBOX1 as left screen and VBOX0 as right screen. I can change it manually and apply the changes and it works during the session, but the system forgets this change - in the next session Vbox1 is again on the left and VBOX0 on the right.
The right window always disappears as described above, whether its vbox0 or vbox1, does not matter. I only mention this 2. problem it, as I assume it could have a common reason and enlighten the main problem. If it should turn out, that its isolate from the other problem I will create its own thread.