Fix checkbox width

flask_admin/static/admin/css/admin.css

@@ -105,3 +105,7 @@ table.filters {
 .select2-results li {
     min-height: 24px !important;
 }
+
+.list-checkbox-column {
+    width: 33px;
+}
\ No newline at end of file

flask_admin/templates/admin/model/list.html

@@ -53,7 +53,7 @@
             <tr>
                 {% block list_header scoped %}
                     {% if actions %}
-                    <th class="span1">
+                    <th class="list-checkbox-column">
                         <input type="checkbox" name="rowtoggle" class="action-rowtoggle" title="{{ _gettext('Select all records') }}" />
                     </th>
                     {% endif %}