Bug with apex:selectCheckboxes in Spring'13 release - checkbox

Question

Right now it seems that anything with the <apex:selectCheckboxes> wont work (regardless of version since I did try bumping it back on both the page and controller). See blog entry for full debugging steps:http://salesforcegirl.blogspot.hu/2013/05/bug-with.html
when trying to use a repeat to populate the Lists via maps it fails as well for both <apex:selectCheckboxes> and <apex:selectList>. But if you do it the long way, you can get <apex:selectList> to work at the very least, however not the <apex:selectCheckboxes> (which is what i need).
Here is the code:
public class sfg_testBugWithActionButton {
public String fGrade {get; set;}
public List<SelectOption> soGrade {get; set;}
public String resultString {get; set;}
public sfg_testBugWithActionButton() {
createfilterMap();
resultString = 'on Load of page';
}
public PageReference preformAction() {
system.debug('Grade: ' + fGrade);//this wont be hit unless you use selectList
resultString = 'button action preformed';
return null;
}
private void createfilterMap() {
soGrade = new List<SelectOption>();
soGrade.add(new SelectOption('A', 'A'));
soGrade.add(new SelectOption('B', 'B'));
soGrade.add(new SelectOption('C', 'C'));
}
}
Page:
<apex:page showHeader="true" sidebar="true" controller="sfg_testBugWithActionButton">
<apex:form>
<apex:outputpanel id="mainWrap">
<h2>Grade</h2>
<apex:selectCheckboxes value="{!fGrade}" layout="pageDirection">
<apex:selectOptions value="{!soGrade}" />
</apex:selectCheckboxes>
<apex:commandButton action="{!preformAction}" rerender="renderWrap" value="Submit Action" />
<br />
<apex:outputpanel id="renderWrap">
{!resultString}
</apex:outputpanel>
</apex:outputpanel>
</apex:form>
</apex:page>

Answer 1

<apex:selectCheckboxes> hold multiple values so its value needs to be an array of strings:
public List<String> fGrade {get; set;}
Then you just need to initialize it in the constructor, and the example in the question works:
this.fGrade = new List<String>();