Visual Studio: Show Solution Platform in Toolbar

link: http://stackoverflow.com/questions/7516755/solution-configuration-but-not-platform-in-vs2010-toolbar

1. On the menubar go to View → Toolbars → Customize...
2. Click on the "Commands" tab
3. Select the "Toolbar" radio button and find "Standard" in the drop down list
4. Click the "Add Command..." button
5. Select the "Build" category
6. Find and select the "Solution Platforms" command and click "OK"
7. Move your new command to a comfortable place on your toolbar using "Move Up" and "Move Down"