formIndex, z-index in responsive forms not working?

I have a seach field as a textbox and I would like to put buttons over it to manipulate the search field data.

I am in fully responsive layout, I can put the button over the textbox using the margin css property with a negative number but the button appears under the textbox.

I’ve tried everything I could to set the z-index property in css or set the formIndex property on the element but I cannot see the change.

Is there any way to change the z-index of form elements easily in a responsive form?

Bump!

I have put this aside for awhile but I need to solve this now, anybody has any pointers on this?