I've written down exactly what I've done:
Visual web developer – new project - New web application
Double click "Site.Master" in solution explorer.
Click "design"
Select the text: "My ASP.NET Application"
Format – font - change color - (not showing change. Opening font again shows the old font color.) Why?
Click on "<h1.style1>
" at bottom
Format – font - change color – (this time it works fine)
Click to the right of "My ASP.NET Application" – div.loginDisplay is selected. Why? Why not the whole header?
Change background color - "My ASP.NET Application" disappears. Why? <- My main question.
Start debugging – "My ASP.NET Application" is shown. Why (since it wasn't showing in visual web developer)?
Honestly, I find the embedded "Design" mode of VSWD to be extremely buggy and certainly not reliable. I don't think you can find a fix for that, because... I believe it wasn't intended to reflect 1:1 state of the webpage, but instead just to show developers just a hint, how it may look like. If you look at video tutorials made by people from Microsoft (Joe Stagner etc.), they all use a real web browser to debug their apps, not a design tab.
So, my advice would be not to rely on a Design tab and use VS like a developer's tool, not some wysiwyg editor.
My suggestion, if you want to get good at web development, remove Design
mode from Visual Studio.
Go to:
Tools > Options > HTML Designer
Then untick Enable HTML designer
Try and get used to only reading the code, and not relying on Visual Studio adding the code for you (badly).