Regression Issue - Content set after an await is not visible

[czuck]

Bug report best practices: https://github.com/xamarin/Xamarin.Forms/wiki/Submitting-Issues

Description

Android only, Master/Detail window opened from master, Content is blank if set after an await

Steps to Reproduce

1. Run the attached app. Label on the detail screen reads "Before the await", then changes to "After the await"
2. Open the Master menu and choose the TestPage option. This opens the same page as step 1. The "Before the await" label is visible, then the view is blank.

Expected Behavior

The window should behave the same in both steps.

Actual Behavior

The second label is not displayed in the second step

Basic Information

• Version with issue: 2.5.0 (and 2.4)
• Last known good version: 2.3.4.270
• IDE: VS2017
• Affected Devices: Android

Reproduction Link

HeaderTest.zip

[PureWeen]

Might be related to
#1736

It seems the issue here is with the ScrollView control. The label is inside a scrollview and when it's set after the await it doesn't render the new label. If you change the container to a StackLayout then it does render the label after the await

I've attached a slim down version of the reproduction. In HeaderPage.cs you'll notice

     // works
            /*Content = new StackLayout
            {
                Children = { _headerPageContent }
            };*/

            // doesn't work
           Content = new ScrollView
            {
                Content = _headerPageContent
            };

The steps to reproduce listed are still the same
HeaderTest.zip

iOS works fine

[czuck]

This is still not working with 3.1.0.583944

[hartez]

@ceblanda Can you expand on that? I've tried @PureWeen's repro with 3.1.0.583944 and it's working.

[czuck]

@hartez, @PureWeen's repo does work, but original repo does not. It appears @PureWeen removed code that is relevant to the original issue.

[hartez]

Looks like we fixed one bug, but there are actually two bugs here.

ScrollView had an update/layout problem on Android, which we fixed. But the same issue also exists for StackLayout (@ceblanda's original repro uses both, and our repro in our UI tests is only using a ScrollView).