You would have to show us the exact situation, preferably with some screen shots.
There must be some special situation there, like the element is locked or its layer is locked or it is part of a Module or something.
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-Ac27