CannotModifyVisualChildrenDuringTreeWalk

What does these exception mean & how to avoid them or is there further documentation. I am modifing the a textblock inlines on binding updates (behavior that formats) inside a datagrid.

Getting this exception from datagrid with virtualization, e.g. virtualized stack panel -> VisualCollection has a guard

VisualCollection.cs, from reference source:

private void ConnectChild(int index, Visual value)
{
    //
    // -- Approved By The Core Team --
    //
    // Do not allow foreign threads to change the tree.
    // (This is a noop if this object is not assigned to a Dispatcher.)
    //
    // We also need to ensure that the tree is homogenous with respect
    // to the dispatchers that the elements belong to.
    //
    _owner.VerifyAccess();
    value.VerifyAccess();

    // It is invalid to modify the children collection that we 
    // might be iterating during a property invalidation tree walk.
    if (_owner.IsVisualChildrenIterationInProgress)
    {
        throw new InvalidOperationException(SR.Get(SRID.CannotModifyVisualChildrenDuringTreeWalk));
    }
}

Meaning of the flag:

// Are we in the process of iterating the visual children. 
// This flag is set during a descendents walk, for property invalidation.
IsVisualChildrenIterationInProgress = 0x00000010

I mean there must be a concept of how to work to avoid this exception with WPF controls either as paradigm or certain checks & code in certain key code paths that I should be aware of. Or where should I turn to get such information?

I clone my question from microsoft forum