Lock Size
To lock an object’s size, click on the object to select it and click the Layout | Size | Lock command. When an object is locked it cannot be resized either through the ribbon W and H boxes, by dragging it with the mouse, or by changing object properties in the Property Manager. Objects that are size locked can be moved on the page.
Repeat the above instructions to unlock a locked object.
When an object's size is locked, the object's visibility check box in
the Object Manager appears with
a lock in the bottom-right corner 
. When
an object's position and size are locked, the box appears with locks in
both lower corners 
.