Closing TabViewItems Does Not Free Used Memory

[lukeblevins]

I'm submitting a...

Bug report (I searched for similar issues and did not find one)

Current behavior

When a user creates a new TabViewItem with a Frame as content, RAM usage will increase for each created item. However, closing one or more of these tabs will keep RAM usage exactly the same with no decrease.

Expected behavior

For many application scenarios, the user expects this memory usage to decrease when the tabs are closed.

Minimal reproduction of the problem with instructions

https://1drv.ms/f/s!AvgU7aa_XojB4kTts9UV5xXGWNfD
Try to create new tabs and monitor memory usage as they are closed.

Environment

Nuget Package(s): Microsoft.Toolkit.Uwp.UI.Controls
Package Version(s): v5.1.1

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [x] May 2019 Update (18362)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [x] May 2019 Update (18362)
- [ ] Insider Build (xxxxx)

Device form factor:
- [x] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [x] 2019 (version: 16.0.3)
- [ ] 2017 Preview (version: )

[lukeblevins]

I presume this is because TabView is based off of ListViewBase (and a StackPanel as the ItemsPanel) which does not seem to dispose of its items when cleared.

[lukeblevins]

I've figured out what causes this behavior to occur. The lack of garbage collection seems to happen when I add TabViewItems to the TabView rather than just setting the ItemSource to an ObservableCollection. (Which makes sense...) I'm going to close this issue now.

[premiaware]

The same problem with memory Leaks is when in the xaml to add the TabViewItems with inside Usercontrol for example:

    <TabView
        TabWidthBehavior="Actual"
        CanCloseTabs="False"
        IsCloseButtonOverlay="False"
        CanDragItems="False"
        CanReorderItems="False"
        AllowDrop="False">
        <controls:TabViewItem>
            <local:RicercaAnagraficaTabAnagraficaUserControl />
        </controls:TabViewItem>
   ……..

In this case when the page that contain the tabView is Disposed the Tabview maintain the usercontrol live.
My solution for fix the problem is derive the TabView

public class TabViewExt : TabView
{
public TabViewExt ()
{
this.DefaultStyleKey = typeof(TabView);
this.Unloaded += TabViewExt_Unloaded;
}

    private void TabViewExt_Unloaded(object sender, RoutedEventArgs e)
    {
        if (this.Items != null)
            this.Items.Clear();
    }
}

If i call Items.Clear(); all working well and the usercontrol is disposed.