Display problems with tiling WMs

[pthfdr]

There is one problem when VirtualBox is displaying text consoles after the update.
It seems to assume the user is using one of those desktop environments.
It used to be fine in VB 5.0:

5.0 screenshot

50.png (42.34 KiB) Viewed 709 times

After updating to 5.1,the screen is totally garbled up:

5.1 screenshot

51.png (54.77 KiB) Viewed 709 times

Even worse,after I switch to another program (terminal emulator) and switched back:
(No,it has nothing to do with GIMP,I have already exited that)

5.1 screenshot after switching tabs

51_1.png (62.98 KiB) Viewed 709 times

(I'm using i3wm in tab mode,by the way.)
Please fix it.