Labels have been overhauled in ARCHICAD 19 so that pane has disappeared as it is no longer relevant in AC19 and later.
The below playlist details all the enhancements made to Labeling in ARCHICAD 19:
https://www.youtube.com/playlist?list=PLnXY6vLUwlWV4o6WaXSS4RR1ZW5CPeFgN
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy
AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac28