NavigationView: The OverflowMenu button will not collapse when the overflow menu only contains one item and NavigationView menu items are removed to empty the overflow menu

[Felix-Dev]

Describe the bug
When the top NavigationView's overflow menu only contains a single menu item and

• either removing that item or
• removing menu item(s) to create enough room for the overflow menu item be displayed in the NavigationView pane area

will not collapse the OverflowMenu button (even though the overflow menu is now empty):

Expected behavior
The OverflowMenu button should be collapsed.

Version Info
NuGet package version:
Microsoft.UI.Xaml 2.5.0-prerelease.200708003
Microsoft.UI.Xaml 2.4.2

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
May 2020 Update (19041)	Yes
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

[marcelwgn]

I think the issue here is that we simply forget to reevaluate the overflow menu situation when the list of NavigationViewItems changes.

[Felix-Dev]

@chingucoding Yes. (I am already working on a fix for this issue.)