Supposing that while debugging with VWD the ASP .NET Development server runs at port 4754. (tray icon).
The page for debug is opening at http://localhost:4750 and every time i have to type in the address bar the correct address. http://localhost:4754
In other words the http://localhost port, is always the ASP .NET Development server port minus 4
Why the page for debug is not opening in the same port with the one shown in the tray icon?
Are you using ESET security?
I had this problem, but I never was able to fix it. I came across this link though, maybe it will help you. Also be sure to check the comments on that page in case the main article didn't resolve the issue.
What are the project settings for the web site in terms of what port to use and what page to open? Are there multiple sites for which another port may be called in to be used?
By default Visual Studio will auto-assign the port. I'm not sure why yours is not syncing the page with the cassini server, but I do you can configure Visual Studio to use a static port instead. Go to your project's options page and look for the Web tab. There should be a Servers sections with an option to Use Visual Studio Development Server and inside of that you can choose Auto-assign Port or Specific port. You could try setting a specific port and see if you get any better results. (These instructions were written using a VS2005 and VB project as a guide- ymmv).