Consider the following scenario: In SharePoint 2010, you have a team site wiki page like http://<siteName>/SitePages/Home.aspx which contains several web parts. You edit the page and add a filter web part. The filter appears to be added successfully, but you cannot see the newly added filter on the page.
The problem occurs because the WebPartManager.DisplayMode property is not getting set when the page is edited. The web parts expect to check WebPartManager.DisplayMode.AllowPageDesign, but for these pages it is set to BrowseDisplayMode even when editing.
To see the filter web part you'll need to select “Edit Web Part" for any of the existing web parts you already have on the page. You can then see the newly added filter web parts you have added to the page and also configure them.
Sharepoint filter webpart wiki