I have noticed that Components disappear after clicking some action buttons in my customized application. Attached is a very simple test example that illustrates the problem. Is this a bug in SalesForce?

Main Visual Page code:

<apex:page standardController="Opportunity" extensions="EditScheduleController">

<apex:form >   
  <apex:pageBlock id="schedule" title="Test">
    <apex:commandButton action="{!refresh}" value="Refresh" reRender="schedule"/>
    <table>
      <tr><c:EditSchedule_OppEditComponent /></tr>
      <tr><c:EditSchedule_OppEditComponent /></tr>
      <tr>
        <td>This is a text from the MAIN page.</td>
      </tr>
      <tr><c:EditSchedule_OppEditComponent /></tr>
    </table>
  </apex:pageBlock>
</apex:form>

</apex:page>

Component "EditSchedule_OppEditComponet.component":

<apex:component >
<td>This is a Component output.</td>
</apex:component>

 Controller "EditScheduleController.cls":

public class EditScheduleController {
  public EditScheduleController(ApexPages.StandardController controller) {
  }
  public PageReference refresh() { return null; }
}

After opening page it looks like:

[Refresh]

This is a Component Output.

This is a Component Output.

This is a text from the MAIN page.

This is a Component Output.

After clicking [Refresh] button all component outputs disappear.

I have noticed some other reports on the same subject (search for "component disappears"):

http://community.salesforce.com/t5/Visualforce-Development/Visualforce-page-disappears-in-Dashboard-refresh/m-p/167442

http://community.salesforce.com/t5/Force-com-Sites/Component-contains-dataTable-rerender-its-disappears/td-p/167798