diff --git a/demo/settingdialog.ui b/demo/settingdialog.ui
index dff4408..b848aa9 100644
--- a/demo/settingdialog.ui
+++ b/demo/settingdialog.ui
@@ -59,13 +59,25 @@
                 <number>6</number>
               </property>
               <item>
-                <widget class="QLineEdit" name="nickEdit" />
+                <widget class="QLineEdit" name="nickEdit">
+                  <property name="maxLength">
+                    <number>200</number>
+                  </property>
+                </widget>
               </item>
               <item>
-                <widget class="QLineEdit" name="roomEdit" />
+                <widget class="QLineEdit" name="roomEdit">
+                  <property name="maxLength">
+                    <number>200</number>
+                  </property>
+                </widget>
               </item>
               <item>
-                <widget class="QLineEdit" name="prefixEdit" />
+                <widget class="QLineEdit" name="prefixEdit">
+                  <property name="maxLength">
+                    <number>200</number>
+                  </property>
+                </widget>
               </item>
             </layout>
           </item>