The Key Color is considered important for developing iOS 7 Overview apps. The concept behind this is:
So Apple is recommending to use a Key Color for their applications following some guidelines:
Consider defining a key color. The built-in apps use key colors—such as yellow in Notes—to indicate interactivity and element state.
Color communicates, but not always in the way you intend. Everyone sees color differently and many cultures differ in how they assign meanings to colors. Spend the time to research how your use of color might be perceived in other countries and cultures. As much as possible, you want to be sure that the colors in your app send the appropriate message.
In most cases, don’t let color distract users. Unless the color is essential to your app’s purpose, it usually works well to use color as a subtle enhancement."
The Key Color can be specified using the Key Color property in the Application Class in the Theme for Smart Devices object.
As from GeneXus X Evolution 2 Upgrade 7 is selected KeyColor is a light color, for instance White, WhiteSmoke or any other light color, the action's color of the following dialogs are set to the platform default blue color:
This property is available as from GeneXus X Evolution 2 Upgrade 4.
Note that as of GeneXus 15 this property is no longer available, and has been replaced by the Action Tint Color property. More information in the Application Colors Properties group document.