Place drawings and parts, and a blue fixed pin 
appears at the top-left corner of the object on the screen. If you click the pin, it turns red 
and the object cannot be selected or edited. When you put the cursor over the object, a "lock" mark appears to the right, indicating that the placement position is fixed.
Releasing Fixed Pins
Releasing individual objects
Double-click a drawing or part, click and the pin turns blue.
Releasing all fixed pins on the screen
From the [Edit (E)] menu, select [Release All Fixed Pins (K)].
Click the pins in the list of drawings and parts displayed in the [Screen Data List] window, and the fixed pins can be set/released.