From Xojo Documentation
Determines whether the top edge of the control should stay at a set distance from the top edge of the parent control, if there is one, or the owning window.
LockTop and LockLeft default to True when you add a control to a window. Existing controls will be altered only if LockRight and/or LockBottom are not set. LockTop has no effect unless LockBottom is True.
This property can be set in the control's Inspector. The following example sets it in code.