diff --git a/R/blocks.R b/R/blocks.R
index 5199559e..e7791de7 100644
--- a/R/blocks.R
+++ b/R/blocks.R
@@ -327,7 +327,10 @@ new_summarize_block <- function(func = character(),
   select_names <- function(funcs) funcs
 
   select_choices <- function(funcs) {
-    replicate(length(funcs), function(data) list(choices = colnames(data)))
+    replicate(
+      length(funcs),
+      set_fun_env(function(data) list(choices = colnames(data)))
+    )
   }
 
   summarize_expr <- function(data, funcs, columns) {
@@ -349,7 +352,7 @@ new_summarize_block <- function(func = character(),
       }
     }
 
-    if (!all(lengths(columns))) {
+    if (!length(columns) || any(!lengths(columns))) {
       return(quote(identity()))
     }
 
diff --git a/R/fields.R b/R/fields.R
index 76eb0059..64a3564d 100644
--- a/R/fields.R
+++ b/R/fields.R
@@ -494,7 +494,7 @@ update_field_components.list_field <- function(x, env = list()) {
 #' @export
 update_field_value.list_field <- function(x, new) {
 
-  if (!length(new)) {
+  if (!length(new) || any(!lengths(new))) {
     return(x)
   }
 
diff --git a/R/utils.R b/R/utils.R
index 5a65c4e4..94d79dc3 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -402,3 +402,11 @@ get_block_title <- function(x) {
 module_server_test <- function(id, x, in_dat, is_prev_valid, ...) {
   generate_server(x = x, in_dat = in_dat, id = id, is_prev_valid = is_prev_valid)
 }
+
+pkg_name <- function() utils::packageName()
+
+pkg_env <- function() asNamespace(pkg_name())
+
+set_fun_env <- function(fun, env = pkg_env()) {
+  `environment<-`(fun, env)
+}