Hi Tuman,
If you need to reset the bounds of the overviewcontrol when the bounds of the Diagram control is changed, then you can go with this by using the Model.SizeToContent property that resizes the Model bounds when the nodes are placed outside ( negative view space ) the model bounds.
The Overviewcontrol''s bounds will also get changed on resizing the Diagram.Model bounds.Please look into the sample image files that will exhibit this behavior.Also, this reset behavior will not zoom the diagram as well.
If I am wrong in getting your requirement,please try to reproduce the issue with the sample or if possible please post us a sample that reproduces the issue.
Thanks for your continued support to Syncfusion.
Regards,
Praveena.
ResetOverViewControlBounds.zip