Yesterday I was creating a simple gantt chart in a project task list. The site master page was blueband,master. I found that you cann’t use gantt chart view in a site that uses a blueband as the master page. the gantt is bigger than the width of master page and it seems bad in the page .
Also I could not change my default master page. So the way I found to solve this problem was to directly change the master page of the view by using SharePoint Designer. I opened the list with SharePoint Designer, opened the gantt.aspx view, and with the use of Format menu and then Master Page Section, I changed the master page of this page.
I now however this page looks different from the other pages in the site , but I did not find any other way till now. This corrected the appearnce of the gantt chart.