Frontend and guest scaling problems on Windows 10

[wilko]

Hi,

Since upgrading VirtualBox from 5.0.x to 5.1.14 today I'm experiencing problems with scaling. Pleas bear with me, I have absolutely no idea what I'm talking about, I'm just going along with what I see (let's call this the naive approach).

My host is a laptop running Windows 10 64 bits. I have 2 monitors, both Dell, but they are different. I was told that one has a lower resolution than the other. I hooked them to my laptop using a HDMI cable for the lower resolution monitor and a DisplayPort cable for the higher resoltution monitor. Three screens with extended desktop, how cool is that.

I had to use Windows Display settings to adjust scaling for the screens, because icons and fonts were unreadably small. So now I have:
1. laptop screen, 3840x1260 (Recommended), scaled at 300%.
2. monitor on DP cable, 3840x1260 (Recommended), scaled at 225% (set as main display)
3. monitor on HDMI cable, 1920x1080 (Recommended), scaled at 100% (Recommended).

I have an Ubuntu (14.04 64 bits 2GB RAM, video mem set to max 128MB, same story applies to 15.x) guest. Each time VirtualBox notifies me of an update, I install it and reinstall the guest additions (!) and if prompted the extension pack.

On VirtualBox 5.0.x (and before, on 4.whatever), I would find that my guest OS icons and fonts were too small so I'd use guest -> View -> Scale factor menu and set scaling to 200%. I could move the guest window between all of my screens without problems.

After upgrading to 5.1.14 (including the extension pack it offers to download), I get a whole range of scaling issues.

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1. the VirtualBox Manager looks totally scrambled after using screen 3. I open VirtualBox Manager, it opens on my main display (2) and looks normal. I move it to screen 3 and icons are Huge, fonts for menu and left VM pane seem normal. The window is huge, for example the scrollbar on the right is twice as wide as it should be, as is the top of the window where the title is (Oracle VM VirtualBox Manager it says in Huge font). The VM details pane has huge font as well. When I move to screen 2 or 1, sometimes, items in the window overlap, for example the menu which then looks like 'FileachinHelp'. Resizing the window returns it to normal on screens 1 and 2, not on 3.

I googled and came across the suggestion to set VirtualBox.exe compatibility (right click the exe in file explorer, Properties, Compatibility tab): disable display scaling on high dpi settings. This did not work. The dialog also offers a 'run compatibility troubleshooter' button, which showed me that I had to run the program in compatibility mode for Windows 8. That results in a normally scaled VirtualBox manager on all of my screens.

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2. Now that my manager is back to normal, I start one of my VMs. This story is equal for any of my guest VMs: Ubuntu 14.04, 15.04, 15.10 and Windows 10, all 64 bits, scaling set to 100% or 200%.

It wants to start on my main screen (2). When I move it to screen 3, the window itself is huge again (I mean with the edges and scrollbar and title huge, regardless of if I make it cover the entire screen, maximise, or make it as small as I can by using the arrow appearing at window edges, normal way of resizing a window). As soon as the guest OS wants to change the display size/resolution during boot (for example going from initial boot to splash screen in Ubuntu, and the again when logging in), the window jumps back from screen 3 to screen 2 and looks normal again. When I move the window back to screen 3, it becomes huge again and it does not resize as I expect it to to fit the screen.

The guest OS itself behaves according to the View -> Scale factor setting. If that is 100%, the guest has fonts and icons at reasonable size for screen 3 and too tiny on screens 1 and 2. If set scale factor to 200%, guest fonts and icons are reasonable size on screens 1 and 2, and Huge on screen 3.

Full screen mode does not make a difference (and I prefer not to use full screen). Scale mode is off, turning it on makes no difference. Switching to Seamless mode (while on any of the screens) throws the window off of the screen alltogether, only to be recovered using Host key + L. Resizing of any kind, whether that is going to full screen or resizing using the arrow that appears at the edge of the window or maximize and back, takes ages, showing a black screen in between.
###

Googling these issues got me:
https://www.virtualbox.org/ticket/15132
viewtopic.php?f=6&t=61891
viewtopic.php?f=6&t=81052&p=380495
All remain unsolved.

In the last topic socratis asks for VM log and vbox file as a zip. I included a screenshot of mangled manager window as it appears on screen 3 before setting compatibiltity mode. I included a screenshot of mangled guest window. I hope it helps, but the issue exists for all guests.

Does anyone know how I can fix this, so I can move my guests between my screens without scaling issues?

[peter_A]

I have a similar issue with a Windows 10 host. In my day-to-day I run in two modes:

Mode 1: Laptop with 2880 x 1800 (Scaled 200%). Mode 2:And as 2 external monitors (1920 x 1080).

Removed from any scaling issues with Guests, I have been fighting major scaling issues with the Virtual Manager itself.

Depending on the order I sign-in and sign-out of Windows, and the order I plug or unplug my monitors -- I get into difficult scaling situations. At times, Virtual Manager text is too small to read, sometimes it is huge. Turning of DPI scaling helps, but only if I unplug/plug and sign in in the correct order.

I get the same issue you have with mulitple monitor resolutions (say if I run with laptop open and external monitor with coarser resolution).

[mikham]

I have the same issue, can I can also confirm that this behavior was introduced in in 5.1.x as previous 5.0.x handled this flawlessly.

Monitor 1 - in host (Windows 10) 2736x1824 with recommended scaling of 200% (this is default for Surface 4 Pro as the text is otherwise way too small in host).
Monitor 2 - in host (Windows 10) 1920x1080 scaling 100%
Monitor 3 - in host (Windows 10) 1920x1080 scaling 100%

VirtualBox is configured with scaling of 200%

Behavior in 5.0.x is that the scaling and/or resolution somehow adapts so that when I drag a window between Monitor 1 and Monitor 2 it automatically works so that window and textsize etc looks correct.

Behavior in 5.1.0-5.1.20 (configured exactly the same way) is that a window in Monitor 1 shows at 400% (or something similar) and when I drag that window to Monitor 2 or 3 it shows with correct scaling. If I change Virtualbox scaling to 100% the resolution/textsizes in Monitor 1 is way too small to be useful but moving a window to Monitor 2/3 and it shows correctly again.

Guest is Ubuntu 16.04, latest VBoxAdditions.

I realize that this may not be sufficient information to troubleshoot the issue, but if someone is willing to have a go at this I can provide more technical data as needed!