Hello,
I'd like to change the property "WindowType" of the standard from "SalesCreateOrder". I've created an extension of the form but still almost all properties are greyed out. How to change the properties of the standard forms if that's possible?

Hello,
I'd like to change the property "WindowType" of the standard from "SalesCreateOrder". I've created an extension of the form but still almost all properties are greyed out. How to change the properties of the standard forms if that's possible?
Not all properties can be modified through extensions. Microsoft has allowed only a few specific properties which you can extend. If you want something else to be extend-able you can raise a request to Microsoft.
Why would want to change the window type of a dialog form anyway? If there is no other way, one option you have is to create a duplicate of this form, modify it in your solution and call it instead of the default form. But in this case any future modifications/upgrades on the form from MS will also remain unavailable in future releases and you may need to do this again in case of any upgrades contradictory to the current form's functionality.