Unable to resize datagrid or its row and column.

Question

Hi I am using a Datagrid in a grid. The parent grid has gridsplitters and whole package is inside a page.
At runtime this page is rendered in a frame which is in a scrollviewer. Following are the major issue I am facing:
1. User unable to resize rows.columns despite setting CanUserResizeRows/Columns property to true.
2. When I try to reduce the gridsize beyond the number of visible rows, it doesn't happen.

Someone please reply.

Thanks in advance.v