I use Fedora 28 with XFCE as a virtual machine in Virtualbox 5.2.12, hosted on Windows 10.

In full screen mode this works really well.

But suddenly I had huge problems with my left mouse button. In some windows it worked, in others it didn’t and vice versa. After trying random things, it worked for some time, then stopped again. Or didn’t work at all.

The system was actually unusable any more.

It took some time until I realized this strange behaviour was caused by the latest kernel update to 4.17

As soon as it was clear I just had to use the old 4.16 kernel the next steps where easy.

1) Exclude the kernel from any further updates.

Edit /etc/dnf/dnf.conf and add the following to the main section:

exclude=kernel*

2) Boot the old kernel by default

Check which kernels are present:

ls -1 /boot/vmlinuz-*
/boot/vmlinuz-0-rescue-3e5e9b5d8fe24678a95a4ccb3eedcb2d
/boot/vmlinuz-4.16.13-300.fc28.x86_64
/boot/vmlinuz-4.17.2-200.fc28.x86_64
/boot/vmlinuz-4.17.3-200.fc28.x86_64

OK. I know 4.16 works. I want to make this kernel the default.

And here comes grubby to the rescue.

Lets verify which one is the default kernel:

sudo grubby --default-kernel
/boot/vmlinuz-4.17.3-200.fc28.x86_64

OK. I know this kernel drives me crazy.

Make 4.16 the default:

sudo grubby --set-default /boot/vmlinuz-4.16.13-300.fc28.x86_64

Verify:

sudo grubby --default-kernel
/boot/vmlinuz-4.16.13-300.fc28.x86_64

The problem is out of the way for now.
The next Virtualbox release should fix this in the long term.