static resources color name

Question

<sys:Double x:Key="Window.Main.Background" >1200</sys:Double>

/////////////////////////////////////////////////////////////////////////////////////

<Window x:Class="DCAD.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:DCAD"
mc:Ignorable="d"
WindowStartupLocation="CenterScreen"
Title="MainWindow"
Width="{StaticResource Window.Main.Background}">

it works , since i copied/pasted it i don't feel comfortable to the name Window.Main.Background the dot,
is it different from WindowMainBackground?
thanks in advance