See beat.editor#205 (comment 40301)

The issue we found first is that the algorithm editor's parameter logic doesn't actually support complex types, but the algorithm schema indicates support. See the algorithm schema, algorithm/common.json:80:

 80     "parameter": {                                                                                                                                                        
 81       "type": "object",                                                                                                                                                   
 82       "properties": {                                                                                                                                                     
 83         "type": { "$ref": "../common/1.json#/definitions/basetype" },                                                                                                     
 84         "default": { "$ref": "../common/1.json#/definitions/value" },                                                                                                     
 85         "description": { "type": "string" }                                                                                                                               
 86       },                                                                                                                                                                  
 87       "required": [                                                                                                                                                       
 88         "type"                                                                                                                                                            
 89       ]                                                                                                                                                                   
 90     },

The type field references the basetype types, which includes complex types, but the editors (beat.web & beat.editor) don't actually support complex types for algorithm parameters.

I'll be looking through the other schemas and will update this issue with other things I find, if any.

EDIT: didn't find anything else in the other objects' schemas parameter definitions