Making Scale and Dimensions independent. Linked Scale

Making Scale and Dimensions independent. Scale and Dimensions of my model seem to be linked and I need to change that. In blender 2.4 there was a button called “Linked Scale” where is that button in Blender 2.68a?

Blender 2.4 Linked Scale: http://wiki.blender.org/index.php/Doc:2.4/Manual/3D_interaction/Transform_Control/Transform_Properties

That button does not exist in any version after 2.49.
With this button the scale and dimensions were linked in just the same way, only the objects proportions were maintained if any scale or dimension value was changed