To save you time, Expression Blend automatically saves the changes that you make to your currently-selected workspace.
For example, if you save your current workspace under the name "Workspace1" and then move a panel, Expression Blend saves the new position of the panel in Workspace1. You could close and reopen Expression Blend, or switch to a different workspace and then switch back to Workspace1, and the panel will be displayed in the new position.
However, Expression Blend does not change the original layout of the Workspace1 preset that you initially saved. You can always return to the original preset by resetting your workspace while in Workspace1. If you do this, the panel that you moved will return to the position it was in when you first saved Workspace1.
For information about how to reset a workspace, see Reset the current workspace.
To create a new workspace preset with the panel in the new position, move the panel and then save the workspace under a new name.