Accessibility Insights: "An onscreen element must not have a null"

[robertmuehsig]

I'm currently try to make our application as accessable as possible and stumbled upon this tool:
https://accessibilityinsights.io/

The tool reports on every ribbon button the following issue:

It appears that the root cause is the implementation of the TwoLineLabel.cs:

If the button text has enough space to be on one line the tool will report an error. If there are two lines everything is fine.

I tried the following in the TwoLineLabel.cs (but this didn't solve all issues, because there are some other code paths) and it "worked":

private void UpdateTextRun()
        {
            ...

                if (string.IsNullOrWhiteSpace(this.textRun2.Text))
                {
                    this.textRun2.Visibility = Visibility.Hidden;
                    // this didn't did the trick:
                    //this.textRun2.SetValue(AutomationProperties.IsOffscreenBehaviorProperty, IsOffscreenBehavior.Offscreen);
                }
            }
        }

When I set the textRun2 to "hidden" it seems to be "better"

Be aware: I'm not an expert in this area. The accessibility tool gives some good hints, but I'm not sure how important those things are.

If you are interested and need help I could try to make a PR. Maybe you could give me a hint if this "code behind" stuff is OK for you or if I should try to put this in the style or somewhere else.

---

Environment

• Fluent.Ribbon v7.1.0
• Windows 10 (v 1903)
• .NET Framework 472 & .NET Core 3

[batzen]

Hiding the second run wouldn't really solve the issue for screen readers. The root cause should be that the control does not provide a proper automation peer. I added quite a few new automation peers but overlooked this one. Will have a look and create a new automation peer.