Screen resolution issues with Win 10 IoT and R Pi Official 7" touchscreen

Question

The official Raspberry Pi 7" Touchscreen Display (https://www.raspberrypi.org/products/raspberry-pi-touch-display/) works really well with Windows 10 IoT Core running on my Raspberry Pi 2 B since support was added back in an Insider Preview (display and touch are functional). Except for the screen resolution. It is almost right, but everything on the screen appears slightly stretched horizontally which gives the app UI a cheap feel. Most notable are circular shapes that are stretched horizontally into an ellipse shape.

I've messed around with values in the config.txt file, which claims to be using 800x480, but no changes seem to have any effect on the screen. Is there any way to make the resolution fit the 800x480 dimensions of the screen better? Below is the config.txt I am using. Please look closely; I am using the custom resolution that everyone suggests. What I'm referring to is a slight stretch in the screen, not a completely incorrect resolution.

# For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md
# Some settings may impact device functionality. See link above for details
# GPU Firmware SHA256 checksum: 7CE2EF13CDD77F1782FFFF98533572503DF4B46765966CC7E18F6C6455B9623A
# kernel.img SHA256 checksum: 8E86F0927DEC464C0D81BBD0B3E7C3FB852FE621853CD4F4E6D38786FAB573E4
# kernel.img git commit ID: 107b92c0ce491ba1e4d0d7068355cafa9da34920

#
# Boot
#
init_uart_clock=16000000    # Set UART clock to 16Mhz
kernel_old=1                # Load kernel.img at physical memory address 0x0
safe_mode_gpio=8            # A temp firmware limitation workaround
max_usb_current=1           # Enable maximum usb current

#
# Memory
#
gpu_mem=32                  # Set VC to 32MB, ARM DRAM to (1008-32)MB
hdmi_force_hotplug=1        # Enable HDMI display even if it is not connected (640x480)

#
# Overclocking
#
core_freq=250               # Frequency of GPU processor core in MHz
force_turbo=1               # Disables dynamic frequency clocking, so that all frequencies and voltages stay high

#
# Video
#
framebuffer_ignore_alpha=1  # Ignore the alpha channel for Windows.
framebuffer_swap=1          # Set the frame buffer to be Windows BGR compatible.
disable_overscan=1          # Disable overscan
hdmi_group=2                # Use VESA Display Mode Timing over CEA
hdmi_mode=87
hdmi_cvt=800 480 60 6 0 0 0 # Add custom 800x480 resolution (group 2 mode 87)

# Rotate the screen and control panel 180
lcd_rotate=2

Answer 1

It looks like this is an issue with the hardware. There are multiple reports of the aspect ratio of this device being off by about 10%.

For example, see https://www.raspberrypi.org/forums/viewtopic.php?t=120710&p=817889