Merge pull request #1771 from MicrosoftDocs/w/yulikl/backBand

This PR simply removes a section from the topic that no longer applies to the product.

Author: garycentric

windows-apps-src/design/basics/navigation-history-and-backwards-navigation.md

@@ -282,17 +282,6 @@ If your app continues using [AppViewBackButtonVisibility](https://docs.microsoft
 
 ![Title bar back button](images/nav-back-pc.png)
 
-### System back bar
-
-> [!NOTE]
-> "System back bar" is only a description, not an official name.
-
-The system back bar is a “band” that is inserted between the tab band and the app’s content area. The band goes across the width of the app, with the back button on the left edge. The band has a vertical height of 32 pixels to ensure adequate touch target size for the back button.
-
-The system back bar is displayed dynamically, based on back button visibility. When the back button is visible, the system back bar is inserted, shifting app content down by 32 pixels below the tab band. When the back button is hidden, the system back bar is dynamically removed, shifting app content up by 32 pixels to meet the tab band. To avoid having your app's UI shift up or down, we recommend drawing an [in-app back button](#back-button).
-
-[Title bar customizations](../shell/title-bar.md) will carry over to both the app tab and the system back bar. If your app specifies background and foreground color properties with [ApplicationViewTitleBar](https://docs.microsoft.com/uwp/api/windows.ui.viewmanagement.applicationviewtitlebar), then the colors will be applied to the tab and system back bar.
-
 ## Guidelines for custom back navigation behavior
 
 If you choose to provide your own back stack navigation, the experience should be consistent with other apps. We recommend that you follow the following patterns for navigation actions: