fix: multiselect dropdown not visible (langflow-ai#3044)

* Fixed refresh button and refresh parameter

* Refactored Multiselect component and implemented custom values on it

* Fixed default values

* Made Backend support combobox on Dropdown and Multiselect

src/backend/base/langflow/inputs/input_mixin.py

@@ -135,17 +135,14 @@ class RangeMixin(BaseModel):
 class DropDownMixin(BaseModel):
     options: Optional[list[str]] = None
     """List of options for the field. Only used when is_list=True. Default is an empty list."""
+    combobox: CoalesceBool = False
+    """Variable that defines if the user can insert custom values in the dropdown."""
 
 
 class MultilineMixin(BaseModel):
     multiline: CoalesceBool = True
 
 
-class ComboboxMixin(BaseModel):
-    combobox: CoalesceBool = False
-    """Variable that defines if the user can insert custom values in the dropdown."""
-
-
 class TableMixin(BaseModel):
     table_schema: Optional[TableSchema | list[Column]] = None
 

src/backend/base/langflow/inputs/inputs.py

@@ -11,7 +11,6 @@
     BaseInputMixin,
     DatabaseLoadMixin,
     DropDownMixin,
-    ComboboxMixin,
     FieldTypes,
     FileMixin,
     InputTraceMixin,
@@ -307,7 +306,7 @@ class DictInput(BaseInputMixin, ListableInputMixin, InputTraceMixin):
     value: Optional[dict] = {}
 
 
-class DropdownInput(BaseInputMixin, DropDownMixin, MetadataTraceMixin, ComboboxMixin):
+class DropdownInput(BaseInputMixin, DropDownMixin, MetadataTraceMixin):
     """
     Represents a dropdown input field.
 
@@ -316,7 +315,7 @@ class DropdownInput(BaseInputMixin, DropDownMixin, MetadataTraceMixin, ComboboxM
 
     Attributes:
         field_type (Optional[SerializableFieldTypes]): The field type of the input. Defaults to FieldTypes.TEXT.
-        options (Optional[Union[list[str], Callable]]): List of options for the field. Only used when is_list=True.
+        options (Optional[Union[list[str], Callable]]): List of options for the field.
             Default is None.
     """
 
@@ -341,6 +340,18 @@ class MultiselectInput(BaseInputMixin, ListableInputMixin, DropDownMixin, Metada
     field_type: Optional[SerializableFieldTypes] = FieldTypes.TEXT
     options: list[str] = Field(default_factory=list)
     is_list: bool = Field(default=True, serialization_alias="list")
+    combobox: CoalesceBool = False
+
+    @field_validator("value")
+    @classmethod
+    def validate_value(cls, v: Any, _info):
+        # Check if value is a list of dicts
+        if not isinstance(v, list):
+            raise ValueError(f"MultiselectInput value must be a list. Value: '{v}'")
+        for item in v:
+            if not isinstance(item, str):
+                raise ValueError(f"MultiselectInput value must be a list of strings. Item: '{item}' is not a string")
+        return v
 
 
 class FileInput(BaseInputMixin, ListableInputMixin, FileMixin, MetadataTraceMixin):