Fix dialog display for yesno and msgbox prompts

barnard-ui

@@ -81,11 +81,18 @@ class ConfigError(Exception):
 DIALOG_OPTS = ["--insecure", "--no-lines", "--visit-items"]
 
 
-def run_dialog(args, stdout=False):
+def run_dialog(args, capture_result=False):
+    """Run dialog.
+
+    dialog draws its widgets on stderr and writes the selected value on stdout
+    when --stdout is used. Keep stderr attached to the terminal for display and
+    only capture stdout when a result is needed.
+    """
     cmd = ["dialog", "--clear"] + DIALOG_OPTS + args
-    if stdout:
+    if capture_result:
         cmd.append("--stdout")
-    return subprocess.run(cmd, capture_output=True, text=True)
+        return subprocess.run(cmd, stdout=subprocess.PIPE, stderr=None, text=True)
+    return subprocess.run(cmd)
 
 
 def msgbox(message):
@@ -101,7 +108,8 @@ def yesno(question):
             question,
             "10",
             "80",
-        ]
+        ],
+        capture_result=False,
     )
     return proc.returncode == 0
 
@@ -117,7 +125,7 @@ def inputbox(instructions, initial=""):
             "0",
             initial,
         ],
-        stdout=True,
+        capture_result=True,
     )
     if proc.returncode != 0:
         return None
@@ -135,7 +143,7 @@ def passwordbox(instructions, initial=""):
             "0",
             initial,
         ],
-        stdout=True,
+        capture_result=True,
     )
     if proc.returncode != 0:
         return None
@@ -161,7 +169,7 @@ def menulist(options):
             "0",
         ]
         + items,
-        stdout=True,
+        capture_result=True,
     )
     if proc.returncode != 0:
         return None