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.