how to position textbox when shown

Question

Hi,

if i have several textboxes in a groupbox that are shown depending on some togglebuttons, how can i display the shown textboxes in sequence?
for example if textbox nr 1 is not shown when a togglebutton is pressed the textbox nr 2 should take the place of textbox nr 1 and nr 3 the place of nr 2 and so on. So it won't be empty space between the boxes.