XmtLayoutDisableLayout() stops the XmtLayout widget w from
recomputing the arrangement of its children when it normally
would. XmtLayoutEnableLayout() restores normal layout computation for w.
Use these functions if you are making an number of changes to
the children of w (managing, unmanaging, repositioning,
resizing) that would cause w to recompute the childrens
arrangement. By batching all the changes between XmtLayoutDisableLayout()
and XmtLayoutEnableLayout() significant
unnecessary computation can be avoided.
Calls to these functions are counted and may be nested-layout
will not be re-enabled until XmtLayoutEnableLayout() has
been called as many times as XmtLayoutDisableLayout().