CB changing width of the tabs: central, left and right

Hi, please, I need help with a layout issue

The position of the flaps, we have the central area, the right of the center and left of the center
it turns out that the three areas have the same size in width, like 3 blocks of equal size 3, 3, 3
[___][___][___]


I need to set the center of the area is larger than the left and the right, something like 2, 5, 1
[__][_____][_]

How can I make this setting in the field widths of these areas?

You need to be more specific as to what tab positions you're using exactly. There's several column usages.