Index: branches/5.2.x/core/admin_templates/incs/form_blocks.tpl
===================================================================
diff -u -N -r16577 -r16620
--- branches/5.2.x/core/admin_templates/incs/form_blocks.tpl	(.../form_blocks.tpl)	(revision 16577)
+++ branches/5.2.x/core/admin_templates/incs/form_blocks.tpl	(.../form_blocks.tpl)	(revision 16620)
@@ -889,11 +889,11 @@
 </inp2:m_DefineElement>
 
 <inp2:m_DefineElement name="inp_checkbox_item">
-	<label class="checkbox" for="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>"><input type="checkbox" <inp2:m_param name='checked'/> id="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>" value="<inp2:m_param name='key'/>" tabindex="<inp2:m_Get name='tab_index'/>" onclick="update_checkbox_options(/^<inp2:{$prefix}_InputName field='$field' as_preg='1'/>_([0-9A-Za-z-]+)/, '<inp2:{$prefix}_InputName field='$field'/>');"><inp2:m_param name="option"/></label><inp2:m_if check="m_Param" name="has_br"><br/><inp2:m_else/>&nbsp;</inp2:m_if>
+	<label class="checkbox" for="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>"><input type="checkbox" <inp2:m_param name='checked'/> id="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>" value="<inp2:m_param name='key'/>" tabindex="<inp2:m_Get name='tab_index'/>" onclick="update_checkbox_options(/^<inp2:{$prefix}_InputName field='$field' as_preg='1'/>_([0-9A-Za-z-_]+)/, '<inp2:{$prefix}_InputName field='$field'/>');"><inp2:m_param name="option"/></label><inp2:m_if check="m_Param" name="has_br"><br/><inp2:m_else/>&nbsp;</inp2:m_if>
 </inp2:m_DefineElement>
 
 <inp2:m_DefineElement name="inp_checkbox_phrase">
-	<label class="checkbox" for="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>"><input type="checkbox" <inp2:m_param name='checked'/> id="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>" value="<inp2:m_param name='key'/>" tabindex="<inp2:m_Get name='tab_index'/>" onclick="update_checkbox_options(/^<inp2:{$prefix}_InputName field='$field' as_preg='1'/>_([0-9A-Za-z-]+)/, '<inp2:{$prefix}_InputName field='$field'/>');"><inp2:m_phrase label="$option"/></label><inp2:m_if check="m_Param" name="has_br"><br/><inp2:m_else/>&nbsp;</inp2:m_if>
+	<label class="checkbox" for="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>"><input type="checkbox" <inp2:m_param name='checked'/> id="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='key'/>" value="<inp2:m_param name='key'/>" tabindex="<inp2:m_Get name='tab_index'/>" onclick="update_checkbox_options(/^<inp2:{$prefix}_InputName field='$field' as_preg='1'/>_([0-9A-Za-z-_]+)/, '<inp2:{$prefix}_InputName field='$field'/>');"><inp2:m_phrase label="$option"/></label><inp2:m_if check="m_Param" name="has_br"><br/><inp2:m_else/>&nbsp;</inp2:m_if>
 </inp2:m_DefineElement>
 
 <inp2:m_DefineElement name="inp_edit_checkboxes" no_empty="" has_br="0">
@@ -910,7 +910,7 @@
 </inp2:m_DefineElement>
 
 <inp2:m_DefineElement name="inp_single_checkbox">
-	<input type="checkbox"<inp2:m_if check="{$prefix}_Selected" field="$field" value="$value"> checked</inp2:m_if> id="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='value'/>" value="<inp2:m_param name='value'/>" onclick="update_checkbox_options(/^<inp2:{$prefix}_InputName field='$field' as_preg='1'/>_([0-9A-Za-z-]+)/, '<inp2:{$prefix}_InputName field='$field'/>');"><label for="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='value'/>"><inp2:$prefix_OptionValue field="$field" value="$value"/></label>&nbsp;
+	<input type="checkbox"<inp2:m_if check="{$prefix}_Selected" field="$field" value="$value"> checked</inp2:m_if> id="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='value'/>" value="<inp2:m_param name='value'/>" onclick="update_checkbox_options(/^<inp2:{$prefix}_InputName field='$field' as_preg='1'/>_([0-9A-Za-z-_]+)/, '<inp2:{$prefix}_InputName field='$field'/>');"><label for="<inp2:{$prefix}_InputName field='$field'/>_<inp2:m_param name='value'/>"><inp2:$prefix_OptionValue field="$field" value="$value"/></label>&nbsp;
 </inp2:m_DefineElement>
 
 <inp2:m_DefineElement name="inp_edit_checkbox_allow_html" field_class="" onchange="" onclick="" title="la_enable_html" hint_label="la_Warning_Enable_HTML">
Index: branches/5.2.x/core/admin_templates/js/grid_filters.js
===================================================================
diff -u -N -r16552 -r16620
--- branches/5.2.x/core/admin_templates/js/grid_filters.js	(.../grid_filters.js)	(revision 16552)
+++ branches/5.2.x/core/admin_templates/js/grid_filters.js	(.../grid_filters.js)	(revision 16620)
@@ -133,7 +133,7 @@
 
 MultiOptions.ItemChecked = function(selector_index) {
 	// sync hidden field
-	var $reg_exp = new RegExp('^_mutlioptions_cb_' + selector_index + '_(?!all)([0-9A-Za-z-]+)');
+	var $reg_exp = new RegExp('^_mutlioptions_cb_' + selector_index + '_(?!all)([0-9A-Za-z-_]+)');
 	update_checkbox_options($reg_exp, MultiOptions.Selectors[selector_index]);
 
 	// update "Select All" checkbox
@@ -160,6 +160,6 @@
 	});
 
 	// sync hidden field
-	var $reg_exp = new RegExp('^_mutlioptions_cb_' + selector_index + '_(?!all)([0-9A-Za-z-]+)');
+	var $reg_exp = new RegExp('^_mutlioptions_cb_' + selector_index + '_(?!all)([0-9A-Za-z-_]+)');
 	update_checkbox_options($reg_exp, MultiOptions.Selectors[selector_index]);
 }