TabControl moves two places..

i have a usercontrol which has a datagrid . i have given textbox column styles for each column
this is the textbox column style that i'm using in the datagrid
//Season Code
nameCodeColumnStyle.MappingName = "Name";
nameCodeColumnStyle.HeaderText = "Name";
nameCodeColumnStyle.Width = 100;
nameCodeColumnStyle.TextBox.TabIndex = 2;

i have four columns...each of textbox column style. i have also given tabindexes for each column.
my problem is at runtime, when i press Tab key in the datagrid, it moves two places .Like if control is on first column, then if i press Tab key to go to the second column, it moves to the third column.
Also if there are buttons, it runns two places ahead...
can any one tell me why this happens, and how to get rid of it..so that Tab control moves on column at a time...
any help will be appreciated...