# Custom Dropdown List [duplicate]

I'm trying to integrate a cutom dropdown in my panel that allows to change between different display types for the created proxy objects.

The script runs without error but the dropdown is not shown in the panel. Also, I get this message in the console pointing to a certain line but I can't figure out what's the problem.

D:\XXXXXXX\XXXXXXXX\XXXXXXXXXX\scripting 2_8 wip.blend\Create Proxy Tools:326 rna_uiItemR: property not found: PROPS_UL_ProxyToolDisplayTypes.DisplayType_List


Edit: Here's a .blend with the script https://1drv.ms/u/s!BH2oRah8e0Ptg8QA9G_pwLDWGUt9ng?e=2yp3rI