VirtualBox

Windows 7 guest only resizes downwards

Problem: Even with the guest tools installed and "View | Auto-resize Guest Display" ticked, Windows 7 only resizes downwards and does not resize to 1440p (or larger) fullscreen.
Solution: In the Display tab of the machine's settings, increase the video memory from 48MB to 128MB.

Problem: PowerPoint shows weird UI glitches such as a slide moving a bit up and down, left and right when clicking on it (in an oscillating manner).
Solution: In the Display tab of the machine's settings, uncheck Enable 3D Acceleration.

Problem: While running PowerPoint on a Windows 7 guest (starting to see a pattern here?), the virtual machine crashed repeatedly when using the clipboard. There was no trace of the crash in the VirtualBox logs and journalctl was also very brief:
```
$ journalctl -xe | grep Virtualbox
[...] audit[74104]: ANOM_ABEND auid=1000 uid=1000 gid=1000 ses=3 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 pid=74104 comm="SHCLX11" exe="/usr/lib/virtualbox/VirtualBoxVM" sig=6 res=1
```
Solution: Disable the shared clipboard until this issue is fixed.

Problem: When using full-screen mode on a Windows 7 guest, the mouse pointer partially stops working on the both the guest and the host operating systems. This means that mouse clicks are not detected in VirtualBox at all (neither inside the virtual machine nor in the VirtualBox GUI). Many other applications (VS Code, Chrome) also face this issue while some others (such as the Terminal Emulerator or the GNOME UI) don't.
Solution: Stop the virtual machine, go to Settings, System and set the pointing device from USB Tablet to USB Multi-Touch Tablet. (Suggested in a loosely related post.)