Creo Interactive Surface Design (Style) > Using Style > User Interface > Modifier Keys
  
Modifier Keys
The following modifier keys are available during Style operations:
Modifier Key
Command
Action
Right-click
All commands
Opens the shortcut menu
Left-click
All commands
Selects by default
CTRL + left-click
Selection
Cancels selection of previously selected entity
Selects multiple entities
Middle-click
All commands
Completes current operation
Repeats
Double-click
Selection
Redefines
SHIFT
Curve Create
Curve Edit
Snaps to existing geometry. When you press the SHIFT key and hold down the mouse button, the pointer is followed by a snap cursor. When the SHIFT key is not pressed, snapping is disabled.
SHIFT + left-click
Surface Edit
Selects a region
CTRL
Selection
Copies geometry then moves
CTRL + SHIFT
Selection
Move geometry without copying
ALT
Curve Create and Edit
Normal drag lock
For more information on configuring the ALT key on UNIX, refer to the topic Enabling the ALT Key.
SHIFT + ALT
Curve Edit
Extend Point
CTRL + ALT
Curve Create and Edit
Horizontal/Vertical drag lock
ALT
Curve Edit
Constrains tangent angle while tangent vector is visible
CTRL + ALT
Curve Edit
Constrains tangent length while tangent vector is visible