fixed the bug which resulted in not showing the grid withotu scrollbars at all

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15118 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/grid.cpp

@@ -3879,6 +3879,10 @@ void wxGrid::CalcDimensions()
     SetScrollbars( GRID_SCROLL_LINE_X, GRID_SCROLL_LINE_Y,
                    GetScrollX(w), GetScrollY(h), x, y,
                    GetBatchCount() != 0);
+
+    // if our OnSize() hadn't been called (it would if we have scrollbars), we
+    // still must reposition the children
+    CalcWindowSizes();
 }