I already tested.
I works with prefilled dropdowns, but not with dynamically filled ones:
[{"id":"912a20c6.5c749","type":"ui_dropdown","z":"416fb8ac.762a48","name":"test","label":"test","tooltip":"","place":"test","group":"deeee64c.743b28","order":3,"width":0,"height":0,"passthru":true,"multiple":false,"options":[{"label":"","value":"","type":"str"}],"payload":"","topic":"test","x":750,"y":900,"wires":[["baf73052.58ae4"]]},{"id":"55f19a36.83c904","type":"inject","z":"416fb8ac.762a48","name":"Setup","props":[{"p":"options","v":"[\"Test 1\",\"Test 2\",\"Test 3\",\"Test 4\",\"Test 5\"]","vt":"json"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payloadType":"str","x":410,"y":880,"wires":[["878ef56.1168008"]]},{"id":"dab6e71b.37ab28","type":"inject","z":"416fb8ac.762a48","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"test_3","payloadType":"str","x":590,"y":920,"wires":[["912a20c6.5c749","6ce0ff1a.b846f"]]},{"id":"baf73052.58ae4","type":"debug","z":"416fb8ac.762a48","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":910,"y":920,"wires":[]},{"id":"878ef56.1168008","type":"function","z":"416fb8ac.762a48","name":"setup data","func":"var newMsg = {\n 'options': []\n};\n\nfor (i = 0; i < 10; i++) {\n const name = 'Test ' + i;\n const id = 'test_' + i;\n var entry = {};\n entry[name] = id;\n newMsg.options.push(entry);\n}\n\nreturn newMsg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":570,"y":880,"wires":[["912a20c6.5c749","dd13caa8.d20698"]]},{"id":"dd13caa8.d20698","type":"debug","z":"416fb8ac.762a48","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":750,"y":860,"wires":[]},{"id":"6ce0ff1a.b846f","type":"ui_dropdown","z":"416fb8ac.762a48","name":"","label":"test","tooltip":"","place":"Select option","group":"deeee64c.743b28","order":4,"width":0,"height":0,"passthru":true,"multiple":false,"options":[{"label":"Test 0","value":"test_0","type":"str"},{"label":"Test 1","value":"test_1","type":"str"},{"label":"Test 2","value":"test_2","type":"str"},{"label":"Test 3","value":"test_3","type":"str"},{"label":"Test 4","value":"test_4","type":"str"},{"label":"Test 5","value":"test_5","type":"str"},{"label":"Test 6","value":"test_6","type":"str"},{"label":"Test 7","value":"test_7","type":"str"},{"label":"Test 8","value":"test_8","type":"str"},{"label":"Test 9","value":"test_9","type":"str"}],"payload":"","topic":"","x":750,"y":940,"wires":[["baf73052.58ae4"]]},{"id":"1b26ffc8.734e4","type":"inject","z":"416fb8ac.762a48","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"test_4","payloadType":"str","x":590,"y":960,"wires":[["912a20c6.5c749","6ce0ff1a.b846f"]]},{"id":"deeee64c.743b28","type":"ui_group","z":"","name":"Information","tab":"cee61e6a.a801e","order":2,"disp":true,"width":"6","collapse":false},{"id":"cee61e6a.a801e","type":"ui_tab","z":"","name":"Konfiguration","icon":"settings","order":1,"disabled":false,"hidden":false}]