Theme “Simplified” not building, “Light” working correctly

I successfully built my project in “light” theme. I was curious about the performance in “simplified,” specifically getting rid of the button animation.

I started a brand new squareline project and replicated the original design. Unfortunately, it will not build, it errors out at the very end of the process.

Any ideas?

Terminal output:

Building in release mode
Compiling .pio\build\JC8048W550\src\main.cpp.o
Linking .pio\build\JC8048W550\firmware.elf
c:/users/htpc/.platformio/packages/toolchain-xtensa-esp32s3/bin/…/lib/gcc/xtensa-esp32s3-elf/8.4.0/…/…/…/…/xtensa-esp32s3-elf/bin/ld.exe: .pio/build/JC8048W550/src/ui/ui.c.o:(.literal.ui_init+0x8): undefined reference to lv_theme_basic_init' c:/users/htpc/.platformio/packages/toolchain-xtensa-esp32s3/bin/../lib/gcc/xtensa-esp32s3-elf/8.4.0/../../../../xtensa-esp32s3-elf/bin/ld.exe: .pio/build/JC8048W550/src/ui/ui.c.o: in function ui_init’:
C:\Users\htpc\Documents\PlatformIO\Door Opener - Simple UI/src/ui/ui.c:237: undefined reference to `lv_theme_basic_init’
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\JC8048W550\firmware.elf] Error 1

What MCU/Processor/Board and compiler are you using?

JC8048W550 / Arduino

What LVGL version are you using?

8.3.1