Context

I installed Ubuntu 21.04 in a Hyper-V VM on Windows 10. It appears to be working great!

I then followed the awesome directions here:

How to install Ubuntu 20.04 on Hyper-V with enhanced session

'Enhanced session' support allows for things like full-screen and multiple monitor support.

This also appears to be working well!

Side note about the instructions there

Edit xrdp.ini

The directions there say:

If you receive an error at the end of the install script, there is one more thing to do. Using your favorite editor, open /etc/xrdp/xrdp.ini

I didn't receive an error, but in order to get the enhanced session support to work, I did have to edit xrdp.ini as he directs.

Hyper-V Quick Create

I used 'Hyper-V Quick Create' to create my VM. I didn't go through all the manual steps he describes there involving UEFI. The VM appears to work fine.

OK, onto the rest of the context for the question.

Full Screen

If I move the size slider all the way up:

it launches full screen which is nice.

My monitor resolution is 3840x2160 so increasing the display scale is desired. When I do so as follows:

it works fine.

Use all my monitors

Now, let's say I log out and reconnect. This time, I select 'Use all my monitors':

Amazingly, this works! I get a desktop across two external monitors and the laptop display. Three screens in all!

This time however, if I go to increase the display scale to 200%:

I hit 'Apply', then 'Keep Changes' in the 'Keep these display settings' dialog. However, it appears to immediately revert to 100% scale.

Question

Is there a way to increase the display scale when connected via the 'Use all my monitors' option?

When trying to build jonesforth, which is a 32-bit GNU Assembler program, on Ubuntu 18.10 64-bit, I get the following message:

~/src/jonesforth $ make
gcc -m32 -nostdlib -static  -o jonesforth jonesforth.S
jonesforth.S:1154:10: fatal error: asm/unistd.h: No such file or directory
 #include <asm/unistd.h>
          ^~~~~~~~~~~~~~
compilation terminated.
make: *** [Makefile:11: jonesforth] Error 1

The source has the following lines:

//#include <asm-i386/unistd.h>  // you might need this instead
#include <asm/unistd.h>

When I try using asm-i386/unistd.h instead, it runs into the same issue.

Is the best course of action to install more headers via sudo apt install linux-headers...? If so, which should I go with? Should linux-headers-generic be sufficient?

Or, should I change the header that jonesforth.S is referring to?

Thanks!

I have a Dell monitor set to a scale of 200%:

I then set the laptop built-in display to 100%:

However, if I then switch back to the Dell monitor settings, the scale there has reverted to 100%.

Is there a way to have 200% scale on the Dell monitor and 100% scale on the laptop monitor?

Thanks!

Is there a way to set up "focus follows mouse" behavior in Unity?