Visual Studio 2013 introduced tooltips displayed over collapsed code blocks. Basically, when you hover the mouse pointer over a collapsed code block, Visual Studio displays a tooltip showing the full content for the selection. The original Visual Studio 2013 tooltips were grayscale; Visual Studio 2015 tooltips are shown in full color. Figure 1 shows an example of colorized tooltips.
Figure 1 Colorized tooltips.
This new feature might seem just a nice addition, but it actually gives you a more immediate view of the selected code block.