Change the active document
When you have multiple documents open at the same time in Microsoft Expression Blend, you can switch between them to change which document is active. (To open a document, double-click the name of the document in the Projects panel.)
Making a document active on the artboard differs from selecting which document will appear first when you run your application (F5).
For more information, see Set a startup document for your project.
Do one of the following:
At the top of the artboard, click the tab for the document that you want to view.
Click the name of the desired document on the Window menu. A check mark will appear next to the document, to show that it is the active document.
Double-click the desired document in the Projects panel.
Hold down the CTRL key and press the TAB key. The Switch To window opens with the name of the next document highlighted. Pressing the TAB key scrolls through the list of open documents. When you release the CTRL key, the highlighted document will become the active document on the artboard.
Click Active files in the upper-right area of the artboard to display the list of open documents, and then click the name of the document that you want to make active.