WebUI: Fix checkbox hidden. Closes #6642.

src/webui/www/public/properties_content.html

@@ -101,7 +101,7 @@
         <table class="dynamicTable" style="width: 100%">
             <thead>
                 <tr>
-                    <th style="width: 30px; border-right: 0"><input type="checkbox" id="tristate_cb" style="display: none;" onclick="javascript:switchCBState()" /><label id="all_files_cb" class="tristate" for="tristate_cb"></label></th>
+                    <th style="width: 4.5em; border-right: 0"><input type="checkbox" id="tristate_cb" style="display: none;" onclick="javascript:switchCBState()" /><label id="all_files_cb" class="tristate" for="tristate_cb"></label></th>
                     <th>QBT_TR(Name)QBT_TR</th>
                     <th style="width: 150px;">QBT_TR(Size)QBT_TR</th>
                     <th style="width: 90px;">QBT_TR(Progress)QBT_TR</th>