In our project, All forms are based on Devexpress XtraForm. Now, Strataframe forms requires to be inhereted from  

MicroFour.StrataFrame.UI.Windows.Forms.StandardForm.  C# does not support Multiple inheretence. At first look, Source code will be changed to be inherited from Devexpress XtraForm. Does it works properly ? Any ideas , Expreriences ?

Where is the source code location to be modified ? 

The StandardForm is not eh root for, it is the BaseForm which is in MicroFour StrataFrame Base.  This form houses all of the required logic by the framework.  You just need to create your own BaseForm and inherit off of the XtraForm and add all of the code from our BaseForm into your custom form.  This is really the only way to achieve this.

BaseForm is in  MicroFour Strataframe Business project. I will copy BaseForm as DevxBaseForm and compile and use StandartForm. Are there another places to be modified ?

Base form is inhereted from Windows.Forms.Form. Why do not we change Windows.Form to Devexpress Form ?

This would require that everyone of the StrataFrame developers purchase a copy of DevExpress...most of our developers do not use DevExpress nor do we want to have a framework the depends on a 3rd party entity.  You are correct though, the BaseForm is in the Business assembly...sorry.

I've changed the BaseForm.vb

as

Public Class BaseForm
        Inherits MyBaseForm
        Implements MicroFour.StrataFrame.UI.Windows.Forms.IContainerControl

MyBaseForm is inhereted from Devexpress XtraForm.

I 've got error message below in design time when strataframe objects were dropped on my form. My form is based on StandartForm which is based on my changed BaseForm.

"The object that the business object has been dropped on must be implement
MicroFour.strataFrame.UI.Windows.Forms.IcontainerControl"

This is a cross-post.  Refer here http://forum.strataframe.net/FindPost14003.aspx.