Hello Ruban,

I am sorry to hear you encountered any issues with the Test Studio project panes in the Visual Studio plugin. 

I tried to reproduce any similar behavior, but I was unable to get to a crash and I will need some additional assistance from your end. 

Can you, please, describe the steps you perform with the Step Builder pane when you get Visual Studio crashed?

• Is this a new Test Studio project created in Visual Studio? 
• If not, can you reproduce the same misbheavior if you create a new project?
• Is the Step Builder pane hidden or you want to change where it is docked? 
• What are the steps you perform to get the crash in Visual Studio? 

In order to gather additional details for the occurrence, it will be helpful to generate some logging when reproducing the misbehavior. So, please, take the time to review the below steps and start Visual Studio with enabled logging, then reproduce the crash.

1. Start an elevated command prompt (with admin privilege).
2. Start Visual Studio 2015 from the command line using the /log switch -  I will recommend you add the argument to specify the file and its location for easier access. 
3. Start the project and reproduce the crash in Visual Studio. 
4. Then, please, collect and send the generated log file zipped via this thread.

I am looking forward to hearing back from you.

Regards,
Elena
Progress Telerik