The work area (user interface) > Structure Browser > Change the Structure Browser width or height
  
Change the Structure Browser width or height
Drag the Structure Browser to change its width or height.
You can set different widths or heights for the following:
Different Creo Elements/Direct Modeling modules.
Both modes of the Structure Browser, docked and floating.
The detailed view as well as the standard Structure Browser view.
The width or height that you have set is maintained when you switch between modules and also across Creo Elements/Direct Modeling sessions.