Savefiledialog and Webbrowser in Wpf

Hello.

I am using Webbrowser in my WPF application and i have two questions.

1- Can I customize the interface of the dialogbox? ie change the title bar and the appearance of the drop-down list. I would also save webbrowser content in HTML, I can do that but I would like to remove the MHT extension in the dialogbox. 

2 - Some pages (CSS3 and HTML5) and or videos are not displayed correctly in my browser  
Is there a way to update the version of webbrowser in  Visual Studio? 

kindly help me.

thank you